20440256 has 28 divisors (see below), whose sum is σ = 42949368. Its totient is φ = 9618432.

The previous prime is 20440249. The next prime is 20440271. The reversal of 20440256 is 65204402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8306 + ... + 10481.

It is an arithmetic number, because the mean of its divisors is an integer number (1533906).

Almost surely, 2^20440256 is an apocalyptic number.

It is an amenable number.

20440256 is an abundant number, since it is smaller than the sum of its proper divisors (22509112).

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

20440256 is a wasteful number, since it uses less digits than its factorization.

20440256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18816 (or 18806 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 20440256 is about 4521.0901340274. The cubic root of 20440256 is about 273.4190543486.

Adding to 20440256 its reverse (65204402), we get a palindrome (85644658).

The spelling of 20440256 in words is "twenty million, four hundred forty thousand, two hundred fifty-six".