256605705 has 32 divisors (see below), whose sum is σ = 461704320. Its totient is φ = 135201600.

The previous prime is 256605689. The next prime is 256605737. The reversal of 256605705 is 507506652.

256605705 is a `hidden beast` number, since 25 + 6 + 60 + 570 + 5 = 666.

It is not a de Polignac number, because 256605705 - 2⁴ = 256605689 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 256605705.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 246 + ... + 22655.

It is an arithmetic number, because the mean of its divisors is an integer number (14428260).

Almost surely, 2^256605705 is an apocalyptic number.

It is an amenable number.

256605705 is a deficient number, since it is larger than the sum of its proper divisors (205098615).

256605705 is a wasteful number, since it uses less digits than its factorization.

256605705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22998 (or 22992 counting only the distinct ones).

The product of its (nonzero) digits is 63000, while the sum is 36.

The square root of 256605705 is about 16018.9170982311. The cubic root of 256605705 is about 635.4608059111.

The spelling of 256605705 in words is "two hundred fifty-six million, six hundred five thousand, seven hundred five".