21158912 has 22 divisors (see below), whose sum is σ = 42299208. Its totient is φ = 10578944.

The previous prime is 21158903. The next prime is 21158933. The reversal of 21158912 is 21985112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9308 + ... + 11355.

Almost surely, 2^21158912 is an apocalyptic number.

It is an amenable number.

21158912 is a deficient number, since it is larger than the sum of its proper divisors (21140296).

21158912 is an equidigital number, since it uses as much as digits as its factorization.

21158912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20683 (or 20665 counting only the distinct ones).

The product of its digits is 1440, while the sum is 29.

The square root of 21158912 is about 4599.8817376102. The cubic root of 21158912 is about 276.5865841347.

The spelling of 21158912 in words is "twenty-one million, one hundred fifty-eight thousand, nine hundred twelve".