256868581 has 8 divisors (see below), whose sum is σ = 275490720. Its totient is φ = 238756752.

The previous prime is 256868551. The next prime is 256868593. The reversal of 256868581 is 185868652.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256868581 is a prime.

It is a super-2 number, since 2×256868581² = 131962935809907122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256868551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126535 + ... + 128548.

It is an arithmetic number, because the mean of its divisors is an integer number (34436340).

Almost surely, 2^256868581 is an apocalyptic number.

It is an amenable number.

256868581 is a deficient number, since it is larger than the sum of its proper divisors (18622139).

256868581 is a wasteful number, since it uses less digits than its factorization.

256868581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255155.

The product of its digits is 921600, while the sum is 49.

The square root of 256868581 is about 16027.1201717589. The cubic root of 256868581 is about 635.6777280617.

The spelling of 256868581 in words is "two hundred fifty-six million, eight hundred sixty-eight thousand, five hundred eighty-one".