20904564 has 24 divisors (see below), whose sum is σ = 48852160. Its totient is φ = 6957504.

The previous prime is 20904511. The next prime is 20904589. The reversal of 20904564 is 46540902.

It is a super-3 number, since 3×20904564³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12777 + ... + 14319.

Almost surely, 2^20904564 is an apocalyptic number.

It is an amenable number.

20904564 is an abundant number, since it is smaller than the sum of its proper divisors (27947596).

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

20904564 is a wasteful number, since it uses less digits than its factorization.

20904564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2679 (or 2677 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 20904564 is about 4572.1509161444. The cubic root of 20904564 is about 275.4738453195.

The spelling of 20904564 in words is "twenty million, nine hundred four thousand, five hundred sixty-four".