91310521 has 4 divisors (see below), whose sum is σ = 91479844. Its totient is φ = 91141200.

The previous prime is 91310509. The next prime is 91310563. The reversal of 91310521 is 12501319.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12501319 = 109 ⋅114691.

It can be written as a sum of positive squares in 2 ways, for example, as 10310521 + 81000000 = 3211^2 + 9000^2 .

It is a cyclic number.

It is not a de Polignac number, because 91310521 - 2⁷ = 91310393 is a prime.

It is a super-2 number, since 2×91310521² = 16675222490582882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91310492 and 91310501.

It is not an unprimeable number, because it can be changed into a prime (91310591) 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, 83850 + ... + 84931.

It is an arithmetic number, because the mean of its divisors is an integer number (22869961).

Almost surely, 2^91310521 is an apocalyptic number.

It is an amenable number.

91310521 is a deficient number, since it is larger than the sum of its proper divisors (169323).

91310521 is a wasteful number, since it uses less digits than its factorization.

91310521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169322.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 91310521 is about 9555.6538761092. The cubic root of 91310521 is about 450.3051773527.

The spelling of 91310521 in words is "ninety-one million, three hundred ten thousand, five hundred twenty-one".