21064642 has 16 divisors (see below), whose sum is σ = 33515712. Its totient is φ = 9907920.

The previous prime is 21064627. The next prime is 21064679. The reversal of 21064642 is 24646012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 948 + ... + 6559.

It is an arithmetic number, because the mean of its divisors is an integer number (2094732).

Almost surely, 2^21064642 is an apocalyptic number.

21064642 is a deficient number, since it is larger than the sum of its proper divisors (12451070).

21064642 is a wasteful number, since it uses less digits than its factorization.

21064642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7593.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 21064642 is about 4589.6232960887. The cubic root of 21064642 is about 276.1752108100.

The spelling of 21064642 in words is "twenty-one million, sixty-four thousand, six hundred forty-two".