256887205591 has 2 divisors, whose sum is σ = 256887205592. Its totient is φ = 256887205590.

The previous prime is 256887205583. The next prime is 256887205609. The reversal of 256887205591 is 195502788652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256887205591 - 2³ = 256887205583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256887202591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128443602795 + 128443602796.

It is an arithmetic number, because the mean of its divisors is an integer number (128443602796).

Almost surely, 2^256887205591 is an apocalyptic number.

256887205591 is a deficient number, since it is larger than the sum of its proper divisors (1).

256887205591 is an equidigital number, since it uses as much as digits as its factorization.

256887205591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096000, while the sum is 58.

The spelling of 256887205591 in words is "two hundred fifty-six billion, eight hundred eighty-seven million, two hundred five thousand, five hundred ninety-one".