256909613 has 4 divisors (see below), whose sum is σ = 261121308. Its totient is φ = 252697920.

The previous prime is 256909607. The next prime is 256909643. The reversal of 256909613 is 316909652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14235529 + 242674084 = 3773^2 + 15578^2 .

It is a cyclic number.

It is not a de Polignac number, because 256909613 - 2²⁰ = 255861037 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 (256909643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2105756 + ... + 2105877.

It is an arithmetic number, because the mean of its divisors is an integer number (65280327).

Almost surely, 2^256909613 is an apocalyptic number.

It is an amenable number.

256909613 is a deficient number, since it is larger than the sum of its proper divisors (4211695).

256909613 is an equidigital number, since it uses as much as digits as its factorization.

256909613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4211694.

The product of its (nonzero) digits is 87480, while the sum is 41.

The square root of 256909613 is about 16028.4002008934. The cubic root of 256909613 is about 635.7115738253.

The spelling of 256909613 in words is "two hundred fifty-six million, nine hundred nine thousand, six hundred thirteen".