256311243 has 8 divisors (see below), whose sum is σ = 379720400. Its totient is φ = 170874144.

The previous prime is 256311239. The next prime is 256311269. The reversal of 256311243 is 342113652.

256311243 is a `hidden beast` number, since 2 + 5 + 631 + 1 + 24 + 3 = 666.

It is not a de Polignac number, because 256311243 - 2² = 256311239 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 9493009 = 256311243 / (2 + 5 + 6 + 3 + 1 + 1 + 2 + 4 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256311443) 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, 4746478 + ... + 4746531.

It is an arithmetic number, because the mean of its divisors is an integer number (47465050).

Almost surely, 2^256311243 is an apocalyptic number.

256311243 is a deficient number, since it is larger than the sum of its proper divisors (123409157).

256311243 is an equidigital number, since it uses as much as digits as its factorization.

256311243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9493018 (or 9493012 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The square root of 256311243 is about 16009.7233892407. The cubic root of 256311243 is about 635.2176433773.

Adding to 256311243 its reverse (342113652), we get a palindrome (598424895).

The spelling of 256311243 in words is "two hundred fifty-six million, three hundred eleven thousand, two hundred forty-three".