21368624 has 20 divisors (see below), whose sum is σ = 41478744. Its totient is φ = 10664448.

The previous prime is 21368617. The next prime is 21368629. The reversal of 21368624 is 42686312.

It is not an unprimeable number, because it can be changed into a prime (21368629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11744 + ... + 13440.

Almost surely, 2^21368624 is an apocalyptic number.

It is an amenable number.

21368624 is a deficient number, since it is larger than the sum of its proper divisors (20110120).

21368624 is a wasteful number, since it uses less digits than its factorization.

21368624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2492 (or 2486 counting only the distinct ones).

The product of its digits is 13824, while the sum is 32.

The square root of 21368624 is about 4622.6209016098. The cubic root of 21368624 is about 277.4973578733.

The spelling of 21368624 in words is "twenty-one million, three hundred sixty-eight thousand, six hundred twenty-four".