21313564 has 6 divisors (see below), whose sum is σ = 37298744. Its totient is φ = 10656780.

The previous prime is 21313547. The next prime is 21313577. The reversal of 21313564 is 46531312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2664192 + ... + 2664199.

Almost surely, 2^21313564 is an apocalyptic number.

It is an amenable number.

21313564 is a deficient number, since it is larger than the sum of its proper divisors (15985180).

21313564 is a wasteful number, since it uses less digits than its factorization.

21313564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5328395 (or 5328393 counting only the distinct ones).

The product of its digits is 2160, while the sum is 25.

The square root of 21313564 is about 4616.6615643774. The cubic root of 21313564 is about 277.2588126999.

Adding to 21313564 its reverse (46531312), we get a palindrome (67844876).

The spelling of 21313564 in words is "twenty-one million, three hundred thirteen thousand, five hundred sixty-four".