21723964 has 12 divisors (see below), whose sum is σ = 38826144. Its totient is φ = 10630784.

The previous prime is 21723959. The next prime is 21723971. The reversal of 21723964 is 46932712.

It is a super-2 number, since 2×21723964² = 943861223746592, which contains 22 as substring.

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, 57589 + ... + 57964.

It is an arithmetic number, because the mean of its divisors is an integer number (3235512).

Almost surely, 2^21723964 is an apocalyptic number.

It is an amenable number.

21723964 is a deficient number, since it is larger than the sum of its proper divisors (17102180).

21723964 is a wasteful number, since it uses less digits than its factorization.

21723964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115604 (or 115602 counting only the distinct ones).

The product of its digits is 18144, while the sum is 34.

The square root of 21723964 is about 4660.8973384961. The cubic root of 21723964 is about 279.0270824975.

The spelling of 21723964 in words is "twenty-one million, seven hundred twenty-three thousand, nine hundred sixty-four".