21059664 has 40 divisors (see below), whose sum is σ = 56163072. Its totient is φ = 6792960.

The previous prime is 21059629. The next prime is 21059669. The reversal of 21059664 is 46695012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21059669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5589 + ... + 8564.

Almost surely, 2^21059664 is an apocalyptic number.

21059664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21059664 is an abundant number, since it is smaller than the sum of its proper divisors (35103408).

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

21059664 is a wasteful number, since it uses less digits than its factorization.

21059664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14195 (or 14189 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 21059664 is about 4589.0809537423. The cubic root of 21059664 is about 276.1534538375.

The spelling of 21059664 in words is "twenty-one million, fifty-nine thousand, six hundred sixty-four".