256721155684 has 48 divisors (see below), whose sum is σ = 543696354432. Its totient is φ = 103541571072.

The previous prime is 256721155661. The next prime is 256721155697. The reversal of 256721155684 is 486551127652.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7058554 + ... + 7094830.

It is an arithmetic number, because the mean of its divisors is an integer number (11327007384).

Almost surely, 2^256721155684 is an apocalyptic number.

It is an amenable number.

256721155684 is an abundant number, since it is smaller than the sum of its proper divisors (286975198748).

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

256721155684 is a wasteful number, since it uses less digits than its factorization.

256721155684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51172 (or 51170 counting only the distinct ones).

The product of its digits is 4032000, while the sum is 52.

The spelling of 256721155684 in words is "two hundred fifty-six billion, seven hundred twenty-one million, one hundred fifty-five thousand, six hundred eighty-four".