21615632 has 10 divisors (see below), whose sum is σ = 41880318. Its totient is φ = 10807808.

The previous prime is 21615617. The next prime is 21615637. The reversal of 21615632 is 23651612.

It can be written as a sum of positive squares in only one way, i.e., 21381376 + 234256 = 4624^2 + 484^2 .

It is not an unprimeable number, because it can be changed into a prime (21615637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 675473 + ... + 675504.

Almost surely, 2^21615632 is an apocalyptic number.

It is an amenable number.

21615632 is a deficient number, since it is larger than the sum of its proper divisors (20264686).

21615632 is a wasteful number, since it uses less digits than its factorization.

21615632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1350985 (or 1350979 counting only the distinct ones).

The product of its digits is 2160, while the sum is 26.

The square root of 21615632 is about 4649.2614467246. The cubic root of 21615632 is about 278.5624965171.

The spelling of 21615632 in words is "twenty-one million, six hundred fifteen thousand, six hundred thirty-two".