256715855850 has 96 divisors (see below), whose sum is σ = 670786781184. Its totient is φ = 64845316800.

The previous prime is 256715855821. The next prime is 256715855857. The reversal of 256715855850 is 58558517652.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (256715855857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5866 + ... + 716565.

It is an arithmetic number, because the mean of its divisors is an integer number (6987362304).

Almost surely, 2^256715855850 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256715855850, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (335393390592).

256715855850 is an abundant number, since it is smaller than the sum of its proper divisors (414070925334).

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

256715855850 is a wasteful number, since it uses less digits than its factorization.

256715855850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 722572 (or 722567 counting only the distinct ones).

The product of its (nonzero) digits is 16800000, while the sum is 57.

The spelling of 256715855850 in words is "two hundred fifty-six billion, seven hundred fifteen million, eight hundred fifty-five thousand, eight hundred fifty".