256311631 has 4 divisors (see below), whose sum is σ = 257130832. Its totient is φ = 255492432.

The previous prime is 256311607. The next prime is 256311641. The reversal of 256311631 is 136113652.

256311631 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 256311631 - 2¹¹ = 256309583 is a prime.

It is a super-2 number, since 2×256311631² = 131391304371760322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 256311631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256311641) 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, 409131 + ... + 409756.

It is an arithmetic number, because the mean of its divisors is an integer number (64282708).

Almost surely, 2^256311631 is an apocalyptic number.

256311631 is a deficient number, since it is larger than the sum of its proper divisors (819201).

256311631 is an equidigital number, since it uses as much as digits as its factorization.

256311631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819200.

The product of its digits is 3240, while the sum is 28.

The square root of 256311631 is about 16009.7355068721. The cubic root of 256311631 is about 635.2179639047.

The spelling of 256311631 in words is "two hundred fifty-six million, three hundred eleven thousand, six hundred thirty-one".