| ||||
---|---|---|---|---|
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.
Because both rearrangements of its digits (17 and 71) are prime numbers, 71 is an emirp and more generally a permutable prime.[1][2] It is the largest number which occurs as a prime factor of an order of a sporadic simple group, the largest (15th) supersingular prime.[3][4]
It is a Pillai prime, since is divisible by 71, but 71 is not one more than a multiple of 9.[5] It is part of the last known pair (71, 7) of Brown numbers, since .[6]