256838457691 has 2 divisors, whose sum is σ = 256838457692. Its totient is φ = 256838457690.

The previous prime is 256838457679. The next prime is 256838457703. The reversal of 256838457691 is 196754838652.

It is a balanced prime because it is at equal distance from previous prime (256838457679) and next prime (256838457703).

It is a cyclic number.

It is not a de Polignac number, because 256838457691 - 2⁷ = 256838457563 is a prime.

It is not a weakly prime, because it can be changed into another prime (256838457661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128419228845 + 128419228846.

It is an arithmetic number, because the mean of its divisors is an integer number (128419228846).

Almost surely, 2^256838457691 is an apocalyptic number.

256838457691 is a deficient number, since it is larger than the sum of its proper divisors (1).

256838457691 is an equidigital number, since it uses as much as digits as its factorization.

256838457691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 87091200, while the sum is 64.

The spelling of 256838457691 in words is "two hundred fifty-six billion, eight hundred thirty-eight million, four hundred fifty-seven thousand, six hundred ninety-one".