91170256531 has 4 divisors (see below), whose sum is σ = 95134180752. Its totient is φ = 87206332312.

The previous prime is 91170256523. The next prime is 91170256543. The reversal of 91170256531 is 13565207119.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13565207119 = 43 ⋅315469933.

It is a cyclic number.

It is not a de Polignac number, because 91170256531 - 2³ = 91170256523 is a prime.

It is a super-2 number, since 2×91170256531² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91170256511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1981962076 + ... + 1981962121.

It is an arithmetic number, because the mean of its divisors is an integer number (23783545188).

Almost surely, 2^91170256531 is an apocalyptic number.

91170256531 is a deficient number, since it is larger than the sum of its proper divisors (3963924221).

91170256531 is a wasteful number, since it uses less digits than its factorization.

91170256531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3963924220.

The product of its (nonzero) digits is 56700, while the sum is 40.

The spelling of 91170256531 in words is "ninety-one billion, one hundred seventy million, two hundred fifty-six thousand, five hundred thirty-one".