21664132 has 12 divisors (see below), whose sum is σ = 43328320. Its totient is φ = 9284616.

The previous prime is 21664117. The next prime is 21664141. The reversal of 21664132 is 23146612.

21664132 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21664097 and 21664106.

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, 386832 + ... + 386887.

Almost surely, 2^21664132 is an apocalyptic number.

It is an amenable number.

21664132 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21664132 is a wasteful number, since it uses less digits than its factorization.

21664132 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 773730 (or 773728 counting only the distinct ones).

The product of its digits is 1728, while the sum is 25.

The square root of 21664132 is about 4654.4744064180. The cubic root of 21664132 is about 278.7706821041.

The spelling of 21664132 in words is "twenty-one million, six hundred sixty-four thousand, one hundred thirty-two".