81756415231 has 2 divisors, whose sum is σ = 81756415232. Its totient is φ = 81756415230.

The previous prime is 81756415207. The next prime is 81756415241. The reversal of 81756415231 is 13251465718.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81756415231 is a prime.

It is a super-2 number, since 2×81756415231² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81756415241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40878207615 + 40878207616.

It is an arithmetic number, because the mean of its divisors is an integer number (40878207616).

Almost surely, 2^81756415231 is an apocalyptic number.

81756415231 is a deficient number, since it is larger than the sum of its proper divisors (1).

81756415231 is an equidigital number, since it uses as much as digits as its factorization.

81756415231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 201600, while the sum is 43.

The spelling of 81756415231 in words is "eighty-one billion, seven hundred fifty-six million, four hundred fifteen thousand, two hundred thirty-one".