256605705999 has 10 divisors (see below), whose sum is σ = 383324573280. Its totient is φ = 171070470612.

The previous prime is 256605705991. The next prime is 256605706013. The reversal of 256605705999 is 999507506652.

256605705999 is a `hidden beast` number, since 2 + 5 + 6 + 6 + 0 + 570 + 59 + 9 + 9 = 666.

It is not a de Polignac number, because 256605705999 - 2³ = 256605705991 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256605705991) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1583985759 + ... + 1583985920.

It is an arithmetic number, because the mean of its divisors is an integer number (38332457328).

Almost surely, 2^256605705999 is an apocalyptic number.

256605705999 is a deficient number, since it is larger than the sum of its proper divisors (126718867281).

256605705999 is an equidigital number, since it uses as much as digits as its factorization.

256605705999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3167971691 (or 3167971682 counting only the distinct ones).

The product of its (nonzero) digits is 45927000, while the sum is 63.

The spelling of 256605705999 in words is "two hundred fifty-six billion, six hundred five million, seven hundred five thousand, nine hundred ninety-nine".