256634431 has 4 divisors (see below), whose sum is σ = 271730592. Its totient is φ = 241538272.

The previous prime is 256634383. The next prime is 256634459. The reversal of 256634431 is 134436652.

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

It is a cyclic number.

It is not a de Polignac number, because 256634431 - 2⁷ = 256634303 is a prime.

It is a super-2 number, since 2×256634431² = 131722462349387522, 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 (256634731) 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, 7548055 + ... + 7548088.

It is an arithmetic number, because the mean of its divisors is an integer number (67932648).

Almost surely, 2^256634431 is an apocalyptic number.

256634431 is a deficient number, since it is larger than the sum of its proper divisors (15096161).

256634431 is a wasteful number, since it uses less digits than its factorization.

256634431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15096160.

The product of its digits is 51840, while the sum is 34.

The square root of 256634431 is about 16019.8137005397. The cubic root of 256634431 is about 635.4845174727.

The spelling of 256634431 in words is "two hundred fifty-six million, six hundred thirty-four thousand, four hundred thirty-one".