91313921 has 4 divisors (see below), whose sum is σ = 91345200. Its totient is φ = 91282644.

The previous prime is 91313917. The next prime is 91313923. The reversal of 91313921 is 12931319.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91313921 - 2² = 91313917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91313923) 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, 10751 + ... + 17268.

It is an arithmetic number, because the mean of its divisors is an integer number (22836300).

Almost surely, 2^91313921 is an apocalyptic number.

It is an amenable number.

91313921 is a deficient number, since it is larger than the sum of its proper divisors (31279).

91313921 is a wasteful number, since it uses less digits than its factorization.

91313921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31278.

The product of its digits is 1458, while the sum is 29.

The square root of 91313921 is about 9555.8317795993. The cubic root of 91313921 is about 450.3107664078.

The spelling of 91313921 in words is "ninety-one million, three hundred thirteen thousand, nine hundred twenty-one".