256525157640 has 32 divisors (see below), whose sum is σ = 769575473280. Its totient is φ = 68406708672.

The previous prime is 256525157621. The next prime is 256525157657. The reversal of 256525157640 is 46751525652.

It is a self number, because there is not a number n which added to its sum of digits gives 256525157640.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1068854704 + ... + 1068854943.

It is an arithmetic number, because the mean of its divisors is an integer number (24049233540).

Almost surely, 2^256525157640 is an apocalyptic number.

256525157640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256525157640 is an abundant number, since it is smaller than the sum of its proper divisors (513050315640).

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

256525157640 is a wasteful number, since it uses less digits than its factorization.

256525157640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2137709661 (or 2137709657 counting only the distinct ones).

The product of its (nonzero) digits is 2520000, while the sum is 48.

The spelling of 256525157640 in words is "two hundred fifty-six billion, five hundred twenty-five million, one hundred fifty-seven thousand, six hundred forty".