256557565 has 32 divisors (see below), whose sum is σ = 348074496. Its totient is φ = 179914560.

The previous prime is 256557527. The next prime is 256557601. The reversal of 256557565 is 565755652.

It is not a de Polignac number, because 256557565 - 2¹⁵ = 256524797 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 195642 + ... + 196948.

It is an arithmetic number, because the mean of its divisors is an integer number (10877328).

Almost surely, 2^256557565 is an apocalyptic number.

It is an amenable number.

256557565 is a deficient number, since it is larger than the sum of its proper divisors (91516931).

256557565 is a wasteful number, since it uses less digits than its factorization.

256557565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1449.

The product of its digits is 1575000, while the sum is 46.

The square root of 256557565 is about 16017.4144293016. The cubic root of 256557565 is about 635.4210653080.

The spelling of 256557565 in words is "two hundred fifty-six million, five hundred fifty-seven thousand, five hundred sixty-five".