256566613 has 8 divisors (see below), whose sum is σ = 260742168. Its totient is φ = 252424704.

The previous prime is 256566599. The next prime is 256566623. The reversal of 256566613 is 316665652.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10484644 + 246081969 = 3238^2 + 15687^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 256566613 - 2⁵ = 256566581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256566623) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7195 + ... + 23767.

It is an arithmetic number, because the mean of its divisors is an integer number (32592771).

Almost surely, 2^256566613 is an apocalyptic number.

It is an amenable number.

256566613 is a deficient number, since it is larger than the sum of its proper divisors (4175555).

256566613 is a wasteful number, since it uses less digits than its factorization.

256566613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16823.

The product of its digits is 194400, while the sum is 40.

The square root of 256566613 is about 16017.6968694004. The cubic root of 256566613 is about 635.4285350055.

The spelling of 256566613 in words is "two hundred fifty-six million, five hundred sixty-six thousand, six hundred thirteen".