256717882639 has 2 divisors, whose sum is σ = 256717882640. Its totient is φ = 256717882638.

The previous prime is 256717882613. The next prime is 256717882711. The reversal of 256717882639 is 936288717652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256717882639 - 2²⁵ = 256684328207 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256717882339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128358941319 + 128358941320.

It is an arithmetic number, because the mean of its divisors is an integer number (128358941320).

Almost surely, 2^256717882639 is an apocalyptic number.

256717882639 is a deficient number, since it is larger than the sum of its proper divisors (1).

256717882639 is an equidigital number, since it uses as much as digits as its factorization.

256717882639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 60963840, while the sum is 64.

The spelling of 256717882639 in words is "two hundred fifty-six billion, seven hundred seventeen million, eight hundred eighty-two thousand, six hundred thirty-nine".