256557456 has 240 divisors, whose sum is σ = 823280640. Its totient is φ = 76982400.

The previous prime is 256557449. The next prime is 256557463. The reversal of 256557456 is 654755652.

256557456 is a `hidden beast` number, since 2 + 56 + 557 + 45 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (256557449) and next prime (256557463).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1698981 + ... + 1699131.

It is an arithmetic number, because the mean of its divisors is an integer number (3430336).

Almost surely, 2^256557456 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 256557456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (411640320).

256557456 is an abundant number, since it is smaller than the sum of its proper divisors (566723184).

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

256557456 is a wasteful number, since it uses less digits than its factorization.

256557456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216 (or 198 counting only the distinct ones).

The product of its digits is 1260000, while the sum is 45.

The square root of 256557456 is about 16017.4110267546. The cubic root of 256557456 is about 635.4209753205.

The spelling of 256557456 in words is "two hundred fifty-six million, five hundred fifty-seven thousand, four hundred fifty-six".