256621724560647 has 16 divisors (see below), whose sum is σ = 402543881664480. Its totient is φ = 161017552665216.

The previous prime is 256621724560603. The next prime is 256621724560763. The reversal of 256621724560647 is 746065427126652.

256621724560647 is a `hidden beast` number, since 2 + 5 + 6 + 6 + 2 + 1 + 7 + 2 + 4 + 560 + 64 + 7 = 666.

It is not a de Polignac number, because 256621724560647 - 2²³ = 256621716172039 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256621724560147) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 279544361808 + ... + 279544362725.

It is an arithmetic number, because the mean of its divisors is an integer number (25158992604030).

Almost surely, 2^{256621724560647} is an apocalyptic number.

256621724560647 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

256621724560647 is a deficient number, since it is larger than the sum of its proper divisors (145922157103833).

256621724560647 is a wasteful number, since it uses less digits than its factorization.

256621724560647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559088724559 (or 559088724553 counting only the distinct ones).

The product of its (nonzero) digits is 203212800, while the sum is 63.

The spelling of 256621724560647 in words is "two hundred fifty-six trillion, six hundred twenty-one billion, seven hundred twenty-four million, five hundred sixty thousand, six hundred forty-seven".