21631504 has 20 divisors (see below), whose sum is σ = 41993964. Its totient is φ = 10794368.

The previous prime is 21631501. The next prime is 21631507. The reversal of 21631504 is 40513612.

It is an interprime number because it is at equal distance from previous prime (21631501) and next prime (21631507).

It can be written as a sum of positive squares in 2 ways, for example, as 11696400 + 9935104 = 3420^2 + 3152^2 .

It is not an unprimeable number, because it can be changed into a prime (21631501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9834 + ... + 11830.

Almost surely, 2^21631504 is an apocalyptic number.

It is an amenable number.

21631504 is a deficient number, since it is larger than the sum of its proper divisors (20362460).

21631504 is a wasteful number, since it uses less digits than its factorization.

21631504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2682 (or 2676 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21631504 is about 4650.9680712729. The cubic root of 21631504 is about 278.6306611092.

The spelling of 21631504 in words is "twenty-one million, six hundred thirty-one thousand, five hundred four".