21664152 has 32 divisors (see below), whose sum is σ = 60178800. Its totient is φ = 7221312.

The previous prime is 21664147. The next prime is 21664163. The reversal of 21664152 is 25146612.

21664152 is a `hidden beast` number, since 2 + 16 + 641 + 5 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49933 + ... + 50364.

Almost surely, 2^21664152 is an apocalyptic number.

It is an amenable number.

21664152 is an abundant number, since it is smaller than the sum of its proper divisors (38514648).

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

21664152 is a wasteful number, since it uses less digits than its factorization.

21664152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100312 (or 100302 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 21664152 is about 4654.4765548878. The cubic root of 21664152 is about 278.7707678897.

The spelling of 21664152 in words is "twenty-one million, six hundred sixty-four thousand, one hundred fifty-two".