21664852 has 24 divisors (see below), whose sum is σ = 41983200. Its totient is φ = 9699360.

The previous prime is 21664849. The next prime is 21664861. The reversal of 21664852 is 25846612.

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, 727 + ... + 6622.

It is an arithmetic number, because the mean of its divisors is an integer number (1749300).

Almost surely, 2^21664852 is an apocalyptic number.

21664852 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21664852 is a deficient number, since it is larger than the sum of its proper divisors (20318348).

21664852 is a wasteful number, since it uses less digits than its factorization.

21664852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7431 (or 7429 counting only the distinct ones).

The product of its digits is 23040, while the sum is 34.

The square root of 21664852 is about 4654.5517507060. The cubic root of 21664852 is about 278.7737703526.

The spelling of 21664852 in words is "twenty-one million, six hundred sixty-four thousand, eight hundred fifty-two".