256366881 has 6 divisors (see below), whose sum is σ = 370307730. Its totient is φ = 170911248.

The previous prime is 256366853. The next prime is 256366909. The reversal of 256366881 is 188663652.

256366881 is a `hidden beast` number, since 2 + 5 + 636 + 6 + 8 + 8 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (256366853) and next prime (256366909).

It can be written as a sum of positive squares in only one way, i.e., 209786256 + 46580625 = 14484^2 + 6825^2 .

It is a de Polignac number, because none of the positive numbers 2^k-256366881 is a prime.

It is a super-2 number, since 2×256366881² = 131447955347336322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (256366181) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14242596 + ... + 14242613.

It is an arithmetic number, because the mean of its divisors is an integer number (61717955).

Almost surely, 2^256366881 is an apocalyptic number.

It is an amenable number.

256366881 is a deficient number, since it is larger than the sum of its proper divisors (113940849).

256366881 is a wasteful number, since it uses less digits than its factorization.

256366881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28485215 (or 28485212 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 256366881 is about 16011.4609264739. The cubic root of 256366881 is about 635.2636027116.

The spelling of 256366881 in words is "two hundred fifty-six million, three hundred sixty-six thousand, eight hundred eighty-one".