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Cardinal | eight hundred | |||
Ordinal | 800th (eight hundredth) | |||
Factorization | 25 × 52 | |||
Greek numeral | Ω´ | |||
Roman numeral | DCCC | |||
Binary | 11001000002 | |||
Ternary | 10021223 | |||
Octal | 14408 | |||
Duodecimal | 56812 | |||
Hexadecimal | 32016 |
800 (eight hundred) is the natural number following 799 and preceding 801.
It is the sum of four consecutive primes (193 + 197 + 199 + 211). It is a Harshad number.
Integers from 801 to 899
800s
- 801 = 32 × 89, Harshad number
- 802 = 2 × 401, sum of eight consecutive primes (83 + 89 + 97 + 101 + 103 + 107 + 109 + 113), nontotient, happy number
- 803 = 11 × 73, sum of three consecutive primes (263 + 269 + 271), sum of nine consecutive primes (71 + 73 + 79 + 83 + 89 + 97 + 101 + 103 + 107), Harshad number
- 804 = 22 × 3 × 67, nontotient, Harshad number
- "The 804" is a local nickname for the Greater Richmond Region of the U.S. state of Virginia, derived from its telephone area code (although the area code covers a larger area).
- 805 = 5 × 7 × 23
- 806 = 2 × 13 × 31, sphenic number, nontotient, totient sum for first 51 integers, happy number
- 807 = 3 × 269
- 808 = 23 × 101, strobogrammatic number[1]
- 809 = prime number, Sophie Germain prime,[2] Chen prime, Eisenstein prime with no imaginary part
810s
- 810 = 2 × 34 × 5, Harshad number
- 811 = prime number, sum of five consecutive primes (151 + 157 + 163 + 167 + 173), Chen prime, happy number, the Mertens function of 811 returns 0
- 812 = 22 × 7 × 29, pronic number,[3] the Mertens function of 812 returns 0
- 813 = 3 × 271
- 814 = 2 × 11 × 37, sphenic number, the Mertens function of 814 returns 0, nontotient
- 815 = 5 × 163
- 816 = 24 × 3 × 17, tetrahedral number,[4] Padovan number,[5] Zuckerman number
- 817 = 19 × 43, sum of three consecutive primes (269 + 271 + 277), centered hexagonal number[6]
- 818 = 2 × 409, nontotient, strobogrammatic number[1]
- 819 = 32 × 7 × 13, square pyramidal number[7]
820s
- 820 = 22 × 5 × 41, triangular number,[8] Harshad number, happy number, repdigit (1111) in base 9
- 821 = prime number, twin prime, Eisenstein prime with no imaginary part, prime quadruplet with 823, 827, 829
- 822 = 2 × 3 × 137, sum of twelve consecutive primes (43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 + 97), sphenic number, member of the Mian–Chowla sequence[9]
- 823 = prime number, twin prime, the Mertens function of 823 returns 0, prime quadruplet with 821, 827, 829
- 824 = 23 × 103, sum of ten consecutive primes (61 + 67 + 71 + 73 + 79 + 83 + 89 + 97 + 101 + 103), the Mertens function of 824 returns 0, nontotient
- 825 = 3 × 52 × 11, Smith number,[10] the Mertens function of 825 returns 0, Harshad number
- 826 = 2 × 7 × 59, sphenic number
- 827 = prime number, twin prime, part of prime quadruplet with {821, 823, 829}, sum of seven consecutive primes (103 + 107 + 109 + 113 + 127 + 131 + 137), Chen prime, Eisenstein prime with no imaginary part, strictly non-palindromic number[11]
- 828 = 22 × 32 × 23, Harshad number
- 829 = prime number, twin prime, part of prime quadruplet with {827, 823, 821}, sum of three consecutive primes (271 + 277 + 281), Chen prime
830s
- 830 = 2 × 5 × 83, sphenic number, sum of four consecutive primes (197 + 199 + 211 + 223), nontotient, totient sum for first 52 integers
- 831 = 3 × 277
- 832 = 26 × 13, Harshad number
- 833 = 72 × 17
- 834 = 2 × 3 × 139, sphenic number, sum of six consecutive primes (127 + 131 + 137 + 139 + 149 + 151), nontotient
- 835 = 5 × 167, Motzkin number[12]
- 836 = 22 × 11 × 19, weird number
- 837 = 33 × 31
- 838 = 2 × 419
- 839 = prime number, safe prime,[13] sum of five consecutive primes (157 + 163 + 167 + 173 + 179), Chen prime, Eisenstein prime with no imaginary part, highly cototient number[14]
840s
- 840 = 23 × 3 × 5 × 7, highly composite number,[15] smallest numbers divisible by the numbers 1 to 8 (lowest common multiple of 1 to 8), sparsely totient number,[16] Harshad number in base 2 through base 10
- 841 = 292 = 202 + 212, sum of three consecutive primes (277 + 281 + 283), sum of nine consecutive primes (73 + 79 + 83 + 89 + 97 + 101 + 103 + 107 + 109), centered square number,[17] centered heptagonal number,[18] centered octagonal number[19]
- 842 = 2 × 421, nontotient
- 843 = 3 × 281, Lucas number[20]
- 844 = 22 × 211, nontotient
- 845 = 5 × 132
- 846 = 2 × 32 × 47, sum of eight consecutive primes (89 + 97 + 101 + 103 + 107 + 109 + 113 + 127), nontotient, Harshad number
- 847 = 7 × 112, happy number
- 848 = 24 × 53
- 849 = 3 × 283, the Mertens function of 849 returns 0
850s
- 850 = 2 × 52 × 17, the Mertens function of 850 returns 0, nontotient, the maximum possible Fair Isaac credit score, country calling code for North Korea
- 851 = 23 × 37
- 852 = 22 × 3 × 71, pentagonal number,[21] Smith number[10]
- country calling code for Hong Kong
- 853 = prime number, Perrin number,[22] the Mertens function of 853 returns 0, average of first 853 prime numbers is an integer (sequence A045345 in the OEIS), strictly non-palindromic number, number of connected graphs with 7 nodes
- country calling code for Macau
- 854 = 2 × 7 × 61, nontotient
- 855 = 32 × 5 × 19, decagonal number,[23] centered cube number[24]
- country calling code for Cambodia
- 856 = 23 × 107, nonagonal number,[25] centered pentagonal number,[26] happy number
- country calling code for Laos
- 857 = prime number, sum of three consecutive primes (281 + 283 + 293), Chen prime, Eisenstein prime with no imaginary part
- 858 = 2 × 3 × 11 × 13, Giuga number[27]
- 859 = prime number
860s
- 860 = 22 × 5 × 43, sum of four consecutive primes (199 + 211 + 223 + 227)
- 861 = 3 × 7 × 41, sphenic number, triangular number,[8] hexagonal number,[28] Smith number[10]
- 862 = 2 × 431
- 863 = prime number, safe prime,[13] sum of five consecutive primes (163 + 167 + 173 + 179 + 181), sum of seven consecutive primes (107 + 109 + 113 + 127 + 131 + 137 + 139), Chen prime, Eisenstein prime with no imaginary part
- 864 = 25 × 33, sum of a twin prime (431 + 433), sum of six consecutive primes (131 + 137 + 139 + 149 + 151 + 157), Harshad number
- 865 = 5 × 173,
- 866 = 2 × 433, nontotient
- 867 = 3 × 172
- 868 = 22 × 7 × 31, nontotient
- 869 = 11 × 79, the Mertens function of 869 returns 0
870s
- 870 = 2 × 3 × 5 × 29, sum of ten consecutive primes (67 + 71 + 73 + 79 + 83 + 89 + 97 + 101 + 103 + 107), pronic number,[3] nontotient, sparsely totient number,[16] Harshad number
- This number is the magic constant of n×n normal magic square and n-queens problem for n = 12.
- 871 = 13 × 67, thirteenth tridecagonal number
- 872 = 23 × 109, nontotient
- 873 = 32 × 97, sum of the first six factorials from 1
- 874 = 2 × 19 × 23, sum of the first twenty-three primes, sum of the first seven factorials from 0, nontotient, Harshad number, happy number
- 875 = 53 × 7, unique expression as difference of positive cubes:[29] 103 - 53
- 876 = 22 × 3 × 73, generalized pentagonal number[30]
- 877 = prime number, Bell number,[31] Chen prime, the Mertens function of 877 returns 0, strictly non-palindromic number.[11]
- 878 = 2 × 439, nontotient
- 879 = 3 × 293, number of regular hypergraphs spanning 4 vertices[32]
880s
- 880 = 24 × 5 × 11, Harshad number; 148-gonal number; the number of n×n magic squares for n = 4.
- country calling code for Bangladesh
- 881 = prime number, twin prime, sum of nine consecutive primes (79 + 83 + 89 + 97 + 101 + 103 + 107 + 109 + 113), Chen prime, Eisenstein prime with no imaginary part, happy number
- 882 = 2 × 32 × 72, Harshad number, totient sum for first 53 integers
- 883 = prime number, twin prime, sum of three consecutive primes (283 + 293 + 307), the Mertens function of 883 returns 0
- 884 = 22 × 13 × 17, the Mertens function of 884 returns 0
- 885 = 3 × 5 × 59, sphenic number
- 886 = 2 × 443, the Mertens function of 886 returns 0
- country calling code for Taiwan
- 887 = prime number followed by primal gap of 20, safe prime,[13] Chen prime, Eisenstein prime with no imaginary part
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- 888 = 23 × 3 × 37, sum of eight consecutive primes (97 + 101 + 103 + 107 + 109 + 113 + 127 + 131), Harshad number, strobogrammatic number,[1] happy number
- 889 = 7 × 127, the Mertens function of 889 returns 0
890s
- 890 = 2 × 5 × 89, sphenic number, sum of four consecutive primes (211 + 223 + 227 + 229), nontotient
- 891 = 34 × 11, sum of five consecutive primes (167 + 173 + 179 + 181 + 191), octahedral number
- 892 = 22 × 223, nontotient
- 893 = 19 × 47, the Mertens function of 893 returns 0
- 894 = 2 × 3 × 149, sphenic number, nontotient
- 895 = 5 × 179, Smith number,[10] Woodall number,[33] the Mertens function of 895 returns 0
- 896 = 27 × 7, sum of six consecutive primes (137 + 139 + 149 + 151 + 157 + 163), the Mertens function of 896 returns 0
- 897 = 3 × 13 × 23, sphenic number
- 898 = 2 × 449, the Mertens function of 898 returns 0, nontotient
- 899 = 29 × 31, happy number
References
- ^ a b c Sloane, N. J. A. (ed.). "Sequence A000787 (Strobogrammatic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A005384 (Sophie Germain primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ a b Sloane, N. J. A. (ed.). "Sequence A002378 (Oblong (or promic, pronic, or heteromecic) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A000292 (Tetrahedral numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A000931 (Padovan sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A003215 (Hex (or centered hexagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A000330 (Square pyramidal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ a b Sloane, N. J. A. (ed.). "Sequence A000217 (Triangular numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A005282 (Mian-Chowla sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ a b c d Sloane, N. J. A. (ed.). "Sequence A006753 (Smith numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ a b Sloane, N. J. A. (ed.). "Sequence A016038 (Strictly non-palindromic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A001006 (Motzkin numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ a b c Sloane, N. J. A. (ed.). "Sequence A005385 (Safe primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A100827 (Highly cototient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A002182 (Highly composite numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ a b Sloane, N. J. A. (ed.). "Sequence A036913 (Sparsely totient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A001844 (Centered square numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A069099 (Centered heptagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A016754 (Odd squares: a(n) = (2n+1)^2. Also centered octagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A000032 (Lucas numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A000326 (Pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A001608 (Perrin sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A001107 (10-gonal (or decagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A005898 (Centered cube numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A001106 (9-gonal (or enneagonal or nonagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A005891 (Centered pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A007850 (Giuga numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A000384 (Hexagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A014439 (Differences between two positive cubes in exactly 1 way.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2019-08-18.
- ^ Sloane, N. J. A. (ed.). "Sequence A001318 (Generalized pentagonal numbers.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2019-08-26.
- ^ Sloane, N. J. A. (ed.). "Sequence A000110 (Bell or exponential numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- ^ Sloane, N. J. A. (ed.). "Sequence A319190 (Number of regular hypergraphs)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2019-08-18.
- ^ Sloane, N. J. A. (ed.). "Sequence A003261 (Woodall numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.