800 (number)
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800 is the natural number following 799 and preceding 801.
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| Ordinal | Eight hundred | ||
| Cardinal | 800th | ||
| Factorization | <math>2^5 \cdot 5^2<math> | ||
| Roman numeral | DCCC | ||
| Binary | 1100100000 | ||
| Hexadecimal | 320 | ||
It is the sum of four consecutive primes (193 + 197 + 199 + 211). It is a Harshad number.
Eight hundred is also:
- The telephone area code for toll-free phone calls in the North American Numbering Plan and some other countries.
- The international direct dial code for toll-free international phone calls.
- In the ISO rating standard (aka ISO 5800), a common film speed for photographic films.
- The flight number of TWA Flight 800
For the year AD, see 800.
801 = 32 × 89, Harshad number
802 = 2 × 401, sum of eight consecutive primes (83 + 89 + 97 + 101 + 103 + 107 + 109 + 113), nontotient, also the telephone area code for American state of Vermont
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
805 = 5 × 7 × 23
806 = 2 × 13 × 31, sphenic number, nontotient
807 = 3 × 269
808 = 23 × 101, also the telephone area code for the American state of Hawaii
809 prime number, Sophie Germain prime
810 = 2 × 34 × 5, Harshad number
811 prime number, sum of five consecutive primes (151 + 157 + 163 + 167 + 173), Mertens function(811) returns 0
812 = 22 × 7 × 29, pronic number, Mertens function(812) returns 0
813 = 3 × 271
814 = 2 × 11 × 37, sphenic number, Mertens function(814) returns 0, nontotient
815 = 5 × 163
816 = 24 × 3 × 17, tetrahedral number
817 = 19 × 43, sum of three consecutive primes (269 + 271 + 277), centered hexagonal number
818 = 2 × 409, nontotient
819 = 32 × 7 × 13, square pyramidal number
820 = 22 × 5 × 41, triangular number, Harshad number
821 prime number
822 = 2 × 3 × 137, sphenic number
823 prime number, Mertens function(823) returns 0
824 = 23 × 103, sum of ten consecutive primes (61 + 67 + 71 + 73 + 79 + 83 + 89 + 97 + 101 + 103), Mertens function(824) returns 0, nontotient
825 = 3 × 52 × 11, Smith number, Mertens function(825) returns 0, Harshad number
826 = 2 × 7 × 59, sphenic number
827 prime number, sum of seven consecutive primes (103 + 107 + 109 + 113 + 127 + 131 + 137), strictly non-palindromic number
828 = 22 × 32 × 23, Harshad number
829 prime number, sum of three consecutive primes (271 + 277 + 281)
830 = 2 × 5 × 83, sphenic number, sum of four consecutive primes (197 + 199 + 211 + 223), nontotient
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
836 = 22 × 11 × 19, weird number
837 = 33 × 31
838 = 2 × 419
839 prime number, safe prime, sum of five consecutive primes (157 + 163 + 167 + 173 + 179), highly cototient number
840 = 23 × 3 × 5 × 7, smallest numbers divisible by the numbers 1 to 8, Harshad number in base 2 thru 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, centered heptagonal number, centered octagonal number
842 = 2 × 421, nontotient
843 = 3 × 281
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
848 = 24 × 53
849 = 3 × 283, Mertens function(849) returns 0
850 = 2 × 52 × 17, Mertens function(850) returns 0, nontotient
851 = 23 × 37
852 = 22 × 3 × 71, Smith number
853 prime number, Mertens function(853) returns 0, strictly non-palindromic number
854 = 2 × 7 × 61, nontotient
855 = 32 × 5 × 19, decagonal number, centered cube number
856 = 23 × 107, nonagonal number, centered pentagonal number
857 prime number, sum of three consecutive primes (281 + 283 + 293)
858 = 2 × 3 × 11 × 13, Giuga number
859 prime number
860 = 22 × 5 × 43, sum of four consecutive primes (199 + 211 + 223 + 227)
861 = 3 × 7 × 41, sphenic number, triangular number, hexagonal number, Smith number
862 = 2 × 431
863 prime number, safe prime, sum of five consecutive primes (163 + 167 + 173 + 179 + 181), sum of seven consecutive primes (107 + 109 + 113 + 127 + 131 + 137 + 139)
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, also the telephone area code for Yukon, Northwest Territories and Nunavut
868 = 22 × 7 × 31, nontotient
869 = 11 × 79, Mertens function(869) returns 0
870 = 2 × 3 × 5 × 29, sum of ten consecutive primes (67 + 71 + 73 + 79 + 83 + 89 + 97 + 101 + 103 + 107), pronic number, nontotient, Harshad number
This number is the magic constant of nxn magic square and n-Queens Problem for n = 12.
871 = 13 × 67
872 = 23 × 109, nontotient
873 = 32 × 97
874 = 2 × 19 × 23, sum of the first twenty-three primes, nontotient, Harshad number
875 = 53 × 7
876 = 22 × 3 × 73
877 prime number, Bell number, Mertens function(877) returns 0, strictly non-palindromic number
878 = 2 × 439, nontotient
879 = 3 × 293
880 = 24 × 5 × 11, Harshad number; 148-gonal number; the number of nxn magic squares for n = 4.
881 prime number, sum of nine consecutive primes (79 + 83 + 89 + 97 + 101 + 103 + 107 + 109 + 113)
882 = 2 × 32 × 72, Harshad number
883 prime number, sum of three consecutive primes (283 + 293 + 307), Mertens function(883) returns 0
884 = 22 × 13 × 17, Mertens function(884) returns 0
885 = 3 × 5 × 59, sphenic number
886 = 2 × 443, Mertens function(886) returns 0
887 prime number, safe prime
888 = 23 × 3 × 37, sum of eight consecutive primes (97 + 101 + 103 + 107 + 109 + 113 + 127 + 131), Harshad number
Also direct dial code for toll-free phone calls in the US.
889 = 7 × 127, Mertens function(889) returns 0
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, Mertens function(893) returns 0
894 = 2 × 3 × 149, sphenic number, nontotient
895 = 5 × 179, Smith number, Woodall number, Mertens function(895) returns 0
896 = 27 × 7, sum of six consecutive primes (137 + 139 + 149 + 151 + 157 + 163), Mertens function(896) returns 0
897 = 3 × 13 × 23, sphenic number
898 = 2 × 449, Mertens function(898) returns 0, nontotient
899 = 29 × 31