256331 has 4 divisors (see below), whose sum is σ = 265200. Its totient is φ = 247464.

The previous prime is 256313. The next prime is 256337. The reversal of 256331 is 133652.

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 256331 - 2¹⁴ = 239947 is a prime.

It is a super-2 number, since 2×256331² = 131411163122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4391 + ... + 4448.

It is an arithmetic number, because the mean of its divisors is an integer number (66300).

2²⁵⁶³³¹ is an apocalyptic number.

256331 is a deficient number, since it is larger than the sum of its proper divisors (8869).

256331 is an equidigital number, since it uses as much as digits as its factorization.

256331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8868.

The product of its digits is 540, while the sum is 20.

The square root of 256331 is about 506.2914180588. The cubic root of 256331 is about 63.5233964254.

Adding to 256331 its reverse (133652), we get a palindrome (389983).

The spelling of 256331 in words is "two hundred fifty-six thousand, three hundred thirty-one".