256631153440656 has 160 divisors (see below), whose sum is σ = 679336262553600. Its totient is φ = 83443593139200.

The previous prime is 256631153440619. The next prime is 256631153440661. The reversal of 256631153440656 is 656044351136652.

It is a junction number, because it is equal to n+sod(n) for n = 256631153440596 and 256631153440605.

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, 1458549135 + ... + 1458725073.

It is an arithmetic number, because the mean of its divisors is an integer number (4245851640960).

Almost surely, 2^{256631153440656} 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 256631153440656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (339668131276800).

256631153440656 is an abundant number, since it is smaller than the sum of its proper divisors (422705109112944).

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

256631153440656 is a wasteful number, since it uses less digits than its factorization.

256631153440656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178157 (or 178151 counting only the distinct ones).

The product of its (nonzero) digits is 46656000, while the sum is 57.

The spelling of 256631153440656 in words is "two hundred fifty-six trillion, six hundred thirty-one billion, one hundred fifty-three million, four hundred forty thousand, six hundred fifty-six".