256643627 has 2 divisors, whose sum is σ = 256643628. Its totient is φ = 256643626.

The previous prime is 256643617. The next prime is 256643669. The reversal of 256643627 is 726346652.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256643627 is a prime.

It is not a weakly prime, because it can be changed into another prime (256643617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128321813 + 128321814.

It is an arithmetic number, because the mean of its divisors is an integer number (128321814).

Almost surely, 2^256643627 is an apocalyptic number.

256643627 is a deficient number, since it is larger than the sum of its proper divisors (1).

256643627 is an equidigital number, since it uses as much as digits as its factorization.

256643627 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 41.

The square root of 256643627 is about 16020.1007175361. The cubic root of 256643627 is about 635.4921078362.

The spelling of 256643627 in words is "two hundred fifty-six million, six hundred forty-three thousand, six hundred twenty-seven".