91313931 has 4 divisors (see below), whose sum is σ = 121751912. Its totient is φ = 60875952.

The previous prime is 91313923. The next prime is 91313939. The reversal of 91313931 is 13931319.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (91313923) and next prime (91313939).

It is not a de Polignac number, because 91313931 - 2³ = 91313923 is a prime.

It is a super-2 number, since 2×91313931² = 16676467989345522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91313939) 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, 15218986 + ... + 15218991.

It is an arithmetic number, because the mean of its divisors is an integer number (30437978).

Almost surely, 2^91313931 is an apocalyptic number.

91313931 is a deficient number, since it is larger than the sum of its proper divisors (30437981).

91313931 is a wasteful number, since it uses less digits than its factorization.

91313931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30437980.

The product of its digits is 2187, while the sum is 30.

The square root of 91313931 is about 9555.8323028400. The cubic root of 91313931 is about 450.3107828459.

The spelling of 91313931 in words is "ninety-one million, three hundred thirteen thousand, nine hundred thirty-one".