256555331 has 2 divisors, whose sum is σ = 256555332. Its totient is φ = 256555330.

The previous prime is 256555307. The next prime is 256555339. The reversal of 256555331 is 133555652.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256555331 is a prime.

It is a super-2 number, since 2×256555331² = 131641275729039122, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 256555291 and 256555300.

It is not a weakly prime, because it can be changed into another prime (256555339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128277665 + 128277666.

It is an arithmetic number, because the mean of its divisors is an integer number (128277666).

Almost surely, 2^256555331 is an apocalyptic number.

256555331 is a deficient number, since it is larger than the sum of its proper divisors (1).

256555331 is an equidigital number, since it uses as much as digits as its factorization.

256555331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 67500, while the sum is 35.

The square root of 256555331 is about 16017.3446925513. The cubic root of 256555331 is about 635.4192209724.

The spelling of 256555331 in words is "two hundred fifty-six million, five hundred fifty-five thousand, three hundred thirty-one".