256507440 has 160 divisors (see below), whose sum is σ = 924036096. Its totient is φ = 57646080.

The previous prime is 256507399. The next prime is 256507453. The reversal of 256507440 is 44705652.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 101229 + ... + 103731.

Almost surely, 2^256507440 is an apocalyptic number.

256507440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256507440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (462018048).

256507440 is an abundant number, since it is smaller than the sum of its proper divisors (667528656).

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

256507440 is a wasteful number, since it uses less digits than its factorization.

256507440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2587 (or 2581 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 33.

The square root of 256507440 is about 16015.8496496439. The cubic root of 256507440 is about 635.3796807616.

The spelling of 256507440 in words is "two hundred fifty-six million, five hundred seven thousand, four hundred forty".