21373564 has 6 divisors (see below), whose sum is σ = 37403744. Its totient is φ = 10686780.

The previous prime is 21373559. The next prime is 21373577. The reversal of 21373564 is 46537312.

It is a congruent number.

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 as a sum of consecutive naturals, namely, 2671692 + ... + 2671699.

Almost surely, 2^21373564 is an apocalyptic number.

It is an amenable number.

21373564 is a deficient number, since it is larger than the sum of its proper divisors (16030180).

21373564 is a wasteful number, since it uses less digits than its factorization.

21373564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5343395 (or 5343393 counting only the distinct ones).

The product of its digits is 15120, while the sum is 31.

The square root of 21373564 is about 4623.1551996445. The cubic root of 21373564 is about 277.5187401786.

The spelling of 21373564 in words is "twenty-one million, three hundred seventy-three thousand, five hundred sixty-four".