20440904 has 64 divisors (see below), whose sum is σ = 44236800. Its totient is φ = 8769600.

The previous prime is 20440891. The next prime is 20440913. The reversal of 20440904 is 40904402.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20440904.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 160889 + ... + 161015.

It is an arithmetic number, because the mean of its divisors is an integer number (691200).

Almost surely, 2^20440904 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 20440904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22118400).

20440904 is an abundant number, since it is smaller than the sum of its proper divisors (23795896).

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

20440904 is a wasteful number, since it uses less digits than its factorization.

20440904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234 (or 230 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 20440904 is about 4521.1617975914. The cubic root of 20440904 is about 273.4219436418.

The spelling of 20440904 in words is "twenty million, four hundred forty thousand, nine hundred four".