21956172 has 48 divisors (see below), whose sum is σ = 61635840. Its totient is φ = 5942592.

The previous prime is 21956159. The next prime is 21956227. The reversal of 21956172 is 27165912.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5283 + ... + 8474.

It is an arithmetic number, because the mean of its divisors is an integer number (1284080).

Almost surely, 2^21956172 is an apocalyptic number.

It is an amenable number.

21956172 is an abundant number, since it is smaller than the sum of its proper divisors (39679668).

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

21956172 is a wasteful number, since it uses less digits than its factorization.

21956172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13790 (or 13788 counting only the distinct ones).

The product of its digits is 7560, while the sum is 33.

The square root of 21956172 is about 4685.7413500961. The cubic root of 21956172 is about 280.0177369716.

The spelling of 21956172 in words is "twenty-one million, nine hundred fifty-six thousand, one hundred seventy-two".