81311179 has 2 divisors, whose sum is σ = 81311180. Its totient is φ = 81311178.

The previous prime is 81311177. The next prime is 81311189. The reversal of 81311179 is 97111318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81311179 - 2¹ = 81311177 is a prime.

It is a super-2 number, since 2×81311179² = 13223015660740082, which contains 22 as substring.

Together with 81311177, it forms a pair of twin primes.

It is equal to p_4741582 and since 81311179 and 4741582 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81311179.

It is not a weakly prime, because it can be changed into another prime (81311177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40655589 + 40655590.

It is an arithmetic number, because the mean of its divisors is an integer number (40655590).

Almost surely, 2^81311179 is an apocalyptic number.

81311179 is a deficient number, since it is larger than the sum of its proper divisors (1).

81311179 is an equidigital number, since it uses as much as digits as its factorization.

81311179 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1512, while the sum is 31.

The square root of 81311179 is about 9017.2711504091. The cubic root of 81311179 is about 433.2282344066.

The spelling of 81311179 in words is "eighty-one million, three hundred eleven thousand, one hundred seventy-nine".