21985912 has 16 divisors (see below), whose sum is σ = 44394840. Its totient is φ = 10147296.

The previous prime is 21985903. The next prime is 21985927. The reversal of 21985912 is 21958912.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105598 + ... + 105805.

Almost surely, 2^21985912 is an apocalyptic number.

It is an amenable number.

21985912 is an abundant number, since it is smaller than the sum of its proper divisors (22408928).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21985912 is a wasteful number, since it uses less digits than its factorization.

21985912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211422 (or 211418 counting only the distinct ones).

The product of its digits is 12960, while the sum is 37.

The square root of 21985912 is about 4688.9137334781. The cubic root of 21985912 is about 280.1441094909.

Subtracting from 21985912 its reverse (21958912), we obtain a cube (27000 = 30³).

The spelling of 21985912 in words is "twenty-one million, nine hundred eighty-five thousand, nine hundred twelve".