256681656 has 384 divisors, whose sum is σ = 949939200. Its totient is φ = 62726400.

The previous prime is 256681637. The next prime is 256681669. The reversal of 256681656 is 656186652.

It is a happy number.

256681656 is a `hidden beast` number, since 2 + 566 + 81 + 6 + 5 + 6 = 666.

Its product of digits (518400) is a multiple of the sum of its prime factors (128).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4207866 + ... + 4207926.

It is an arithmetic number, because the mean of its divisors is an integer number (2473800).

Almost surely, 2^256681656 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 256681656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (474969600).

256681656 is an abundant number, since it is smaller than the sum of its proper divisors (693257544).

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

256681656 is a wasteful number, since it uses less digits than its factorization.

256681656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128 (or 107 counting only the distinct ones).

The product of its digits is 518400, while the sum is 45.

The square root of 256681656 is about 16021.2875887052. The cubic root of 256681656 is about 635.5234949858.

The spelling of 256681656 in words is "two hundred fifty-six million, six hundred eighty-one thousand, six hundred fifty-six".