21164944 has 20 divisors (see below), whose sum is σ = 41962096. Its totient is φ = 10336032.

The previous prime is 21164939. The next prime is 21164953. The reversal of 21164944 is 44946112.

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 3 ways as a sum of consecutive naturals, for example, 14694 + ... + 16069.

Almost surely, 2^21164944 is an apocalyptic number.

It is an amenable number.

21164944 is a deficient number, since it is larger than the sum of its proper divisors (20797152).

21164944 is a wasteful number, since it uses less digits than its factorization.

21164944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30814 (or 30808 counting only the distinct ones).

The product of its digits is 6912, while the sum is 31.

The square root of 21164944 is about 4600.5373599179. The cubic root of 21164944 is about 276.6128648143.

The spelling of 21164944 in words is "twenty-one million, one hundred sixty-four thousand, nine hundred forty-four".