256642959 has 4 divisors (see below), whose sum is σ = 342190616. Its totient is φ = 171095304.

The previous prime is 256642949. The next prime is 256642973. The reversal of 256642959 is 959246652.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 256642959 - 2⁴ = 256642943 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 (256642949) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42773824 + ... + 42773829.

It is an arithmetic number, because the mean of its divisors is an integer number (85547654).

Almost surely, 2^256642959 is an apocalyptic number.

256642959 is a deficient number, since it is larger than the sum of its proper divisors (85547657).

256642959 is an equidigital number, since it uses as much as digits as its factorization.

256642959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85547656.

The product of its digits is 1166400, while the sum is 48.

The square root of 256642959 is about 16020.0798687148. The cubic root of 256642959 is about 635.4915564762.

The spelling of 256642959 in words is "two hundred fifty-six million, six hundred forty-two thousand, nine hundred fifty-nine".