91215925 has 12 divisors (see below), whose sum is σ = 113688036. Its totient is φ = 72598400.

The previous prime is 91215899. The next prime is 91215937. The reversal of 91215925 is 52951219.

It can be written as a sum of positive squares in 6 ways, for example, as 23746129 + 67469796 = 4873^2 + 8214^2 .

It is not a de Polignac number, because 91215925 - 2⁹ = 91215413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4336 + ... + 14185.

It is an arithmetic number, because the mean of its divisors is an integer number (9474003).

Almost surely, 2^91215925 is an apocalyptic number.

It is an amenable number.

91215925 is a deficient number, since it is larger than the sum of its proper divisors (22472111).

91215925 is a wasteful number, since it uses less digits than its factorization.

91215925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18728 (or 18723 counting only the distinct ones).

The product of its digits is 8100, while the sum is 34.

The square root of 91215925 is about 9550.7028537171. The cubic root of 91215925 is about 450.1496210287.

The spelling of 91215925 in words is "ninety-one million, two hundred fifteen thousand, nine hundred twenty-five".