21064572 has 36 divisors (see below), whose sum is σ = 53647776. Its totient is φ = 6968640.

The previous prime is 21064567. The next prime is 21064579. The reversal of 21064572 is 27546012.

21064572 is a `hidden beast` number, since 2 + 10 + 645 + 7 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064579) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2797 + ... + 7067.

It is an arithmetic number, because the mean of its divisors is an integer number (1490216).

Almost surely, 2^21064572 is an apocalyptic number.

It is an amenable number.

21064572 is an abundant number, since it is smaller than the sum of its proper divisors (32583204).

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

21064572 is a wasteful number, since it uses less digits than its factorization.

21064572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4418 (or 4413 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21064572 is about 4589.6156701842. The cubic root of 21064572 is about 276.1749048900.

The spelling of 21064572 in words is "twenty-one million, sixty-four thousand, five hundred seventy-two".