20904804 has 84 divisors (see below), whose sum is σ = 56188944. Its totient is φ = 6800112.

The previous prime is 20904803. The next prime is 20904811. The reversal of 20904804 is 40840902.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20904803) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 195319 + ... + 195425.

It is an arithmetic number, because the mean of its divisors is an integer number (668916).

Almost surely, 2^20904804 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20904804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28094472).

20904804 is an abundant number, since it is smaller than the sum of its proper divisors (35284140).

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

20904804 is a wasteful number, since it uses less digits than its factorization.

20904804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196 (or 179 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 20904804 is about 4572.1771619219. The cubic root of 20904804 is about 275.4748995306.

The spelling of 20904804 in words is "twenty million, nine hundred four thousand, eight hundred four".