| ||||
|---|---|---|---|---|
| Cardinal | seventy-one | |||
| Ordinal | 71st (seventy-first) | |||
| Factorization | prime | |||
| Prime | 20th | |||
| Divisors | 1, 71 | |||
| Greek numeral | ΟΑ´ | |||
| Roman numeral | LXXI | |||
| Binary | 10001112 | |||
| Ternary | 21223 | |||
| Senary | 1556 | |||
| Octal | 1078 | |||
| Duodecimal | 5B12 | |||
| Hexadecimal | 4716 | |||
71 (seventy-one) is the natural number following 70 and preceding 72.
71 is the 20th prime number. Because both rearrangements of its digits (17 and 71) are prime numbers, 71 is an emirp and more generally a permutable prime. [1] [2]
71 is a centered heptagonal number. [3]
It is a Pillai prime, since is divisible by 71, but 71 is not one more than a multiple of 9. [4] It is part of the last known pair (71, 7) of Brown numbers, since . [5]
71 is the smallest of thirty-one discriminants of imaginary quadratic fields with class number of 7, negated (see also, Heegner numbers). [6]
71 is the largest number which occurs as a prime factor of an order of a sporadic simple group, the largest (15th) supersingular prime. [7] [8]
23 (twenty-three) is the natural number following 22 and preceding 24.
29 (twenty-nine) is the natural number following 28 and preceding 30. It is a prime number.
79 (seventy-nine) is the natural number following 78 and preceding 80.
73 (seventy-three) is the natural number following 72 and preceding 74. In English, it is the smallest natural number with twelve letters in its spelled out name.
31 (thirty-one) is the natural number following 30 and preceding 32. It is a prime number.
37 (thirty-seven) is the natural number following 36 and preceding 38.
1000 or one thousand is the natural number following 999 and preceding 1001. In most English-speaking countries, it can be written with or without a comma or sometimes a period separating the thousands digit: 1,000.
300 is the natural number following 299 and preceding 301.
400 is the natural number following 399 and preceding 401.
500 is the natural number following 499 and preceding 501.
700 is the natural number following 699 and preceding 701.
600 is the natural number following 599 and preceding 601.
1729 is the natural number following 1728 and preceding 1730. It is the first nontrivial taxicab number, expressed as the sum of two cubic numbers in two different ways. It is also known as the Ramanujan number or Hardy–Ramanujan number, named after G. H. Hardy and Srinivasa Ramanujan.
3000 is the natural number following 2999 and preceding 3001. It is the smallest number requiring thirteen letters in English.
4000 is the natural number following 3999 and preceding 4001. It is a decagonal number.
7000 is the natural number following 6999 and preceding 7001.
131 is the natural number following 130 and preceding 132.
A centered heptagonal number is a centered figurate number that represents a heptagon with a dot in the center and all other dots surrounding the center dot in successive heptagonal layers. The centered heptagonal number for n is given by the formula
233 is the natural number following 232 and preceding 234.
307 is the natural number following 306 and preceding 308.
