21664010 has 16 divisors (see below), whose sum is σ = 39108096. Its totient is φ = 8640528.

The previous prime is 21664007. The next prime is 21664037. The reversal of 21664010 is 1046612.

It is a happy 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, 719 + ... + 6621.

It is an arithmetic number, because the mean of its divisors is an integer number (2444256).

Almost surely, 2^21664010 is an apocalyptic number.

21664010 is a deficient number, since it is larger than the sum of its proper divisors (17444086).

21664010 is a wasteful number, since it uses less digits than its factorization.

21664010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6277.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21664010 is about 4654.4613007307. The cubic root of 21664010 is about 278.7701588108.

The spelling of 21664010 in words is "twenty-one million, six hundred sixty-four thousand, ten".