21632644 has 12 divisors (see below), whose sum is σ = 41298768. Its totient is φ = 9833000.

The previous prime is 21632641. The next prime is 21632647. The reversal of 21632644 is 44623612.

It is an interprime number because it is at equal distance from previous prime (21632641) and next prime (21632647).

It is not an unprimeable number, because it can be changed into a prime (21632641) 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, 245782 + ... + 245869.

It is an arithmetic number, because the mean of its divisors is an integer number (3441564).

Almost surely, 2^21632644 is an apocalyptic number.

It is an amenable number.

21632644 is a deficient number, since it is larger than the sum of its proper divisors (19666124).

21632644 is a wasteful number, since it uses less digits than its factorization.

21632644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491666 (or 491664 counting only the distinct ones).

The product of its digits is 6912, while the sum is 28.

The square root of 21632644 is about 4651.0906247890. The cubic root of 21632644 is about 278.6355557199.

The spelling of 21632644 in words is "twenty-one million, six hundred thirty-two thousand, six hundred forty-four".