256511616264 has 128 divisors (see below), whose sum is σ = 743887123200. Its totient is φ = 81745044480.

The previous prime is 256511616233. The next prime is 256511616281. The reversal of 256511616264 is 462616115652.

256511616264 is a `hidden beast` number, since 2 + 5 + 6 + 5 + 1 + 1 + 616 + 26 + 4 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10723902 + ... + 10747794.

It is an arithmetic number, because the mean of its divisors is an integer number (5811618150).

Almost surely, 2^256511616264 is an apocalyptic number.

256511616264 is a gapful number since it is divisible by the number (24) 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 256511616264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (371943561600).

256511616264 is an abundant number, since it is smaller than the sum of its proper divisors (487375506936).

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

256511616264 is a wasteful number, since it uses less digits than its factorization.

256511616264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26092 (or 26082 counting only the distinct ones).

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

The spelling of 256511616264 in words is "two hundred fifty-six billion, five hundred eleven million, six hundred sixteen thousand, two hundred sixty-four".