20389904 has 20 divisors (see below), whose sum is σ = 39761964. Its totient is φ = 10128768.

The previous prime is 20389903. The next prime is 20389913. The reversal of 20389904 is 40998302.

It can be written as a sum of positive squares in 2 ways, for example, as 12816400 + 7573504 = 3580^2 + 2752^2 .

It is not an unprimeable number, because it can be changed into a prime (20389903) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1547 + ... + 6570.

Almost surely, 2^20389904 is an apocalyptic number.

It is an amenable number.

20389904 is a deficient number, since it is larger than the sum of its proper divisors (19372060).

20389904 is a wasteful number, since it uses less digits than its factorization.

20389904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8282 (or 8276 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 20389904 is about 4515.5181319534. The cubic root of 20389904 is about 273.1943585929.

The spelling of 20389904 in words is "twenty million, three hundred eighty-nine thousand, nine hundred four".