20904080 has 20 divisors (see below), whose sum is σ = 48602172. Its totient is φ = 8361600.

The previous prime is 20904077. The next prime is 20904089. The reversal of 20904080 is 8040902.

It can be written as a sum of positive squares in 2 ways, for example, as 8737936 + 12166144 = 2956^2 + 3488^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (20904089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130571 + ... + 130730.

Almost surely, 2^20904080 is an apocalyptic number.

20904080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20904080 is an abundant number, since it is smaller than the sum of its proper divisors (27698092).

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

20904080 is a wasteful number, since it uses less digits than its factorization.

20904080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261314 (or 261308 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 20904080 is about 4572.0979867015. The cubic root of 20904080 is about 275.4717193026.

Adding to 20904080 its reverse (8040902), we get a palindrome (28944982).

The spelling of 20904080 in words is "twenty million, nine hundred four thousand, eighty".