256521388 has 12 divisors (see below), whose sum is σ = 450500680. Its totient is φ = 127806912.

The previous prime is 256521361. The next prime is 256521427. The reversal of 256521388 is 883125652.

256521388 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 256521388.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112173 + ... + 114436.

Almost surely, 2^256521388 is an apocalyptic number.

It is an amenable number.

256521388 is a deficient number, since it is larger than the sum of its proper divisors (193979292).

256521388 is a wasteful number, since it uses less digits than its factorization.

256521388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226896 (or 226894 counting only the distinct ones).

The product of its digits is 115200, while the sum is 40.

The square root of 256521388 is about 16016.2850873728. The cubic root of 256521388 is about 635.3911971464.

The spelling of 256521388 in words is "two hundred fifty-six million, five hundred twenty-one thousand, three hundred eighty-eight".