256581863 has 8 divisors (see below), whose sum is σ = 258132480. Its totient is φ = 255036600.

The previous prime is 256581841. The next prime is 256581869. The reversal of 256581863 is 368185652.

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

It is a cyclic number.

It is not a de Polignac number, because 256581863 - 2¹⁶ = 256516327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256581869) 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, 130538 + ... + 132488.

It is an arithmetic number, because the mean of its divisors is an integer number (32266560).

Almost surely, 2^256581863 is an apocalyptic number.

256581863 is a deficient number, since it is larger than the sum of its proper divisors (1550617).

256581863 is a wasteful number, since it uses less digits than its factorization.

256581863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2677.

The product of its digits is 345600, while the sum is 44.

The square root of 256581863 is about 16018.1728983052. The cubic root of 256581863 is about 635.4411244497.

The spelling of 256581863 in words is "two hundred fifty-six million, five hundred eighty-one thousand, eight hundred sixty-three".