256608909 has 6 divisors (see below), whose sum is σ = 370657326. Its totient is φ = 171072600.

The previous prime is 256608901. The next prime is 256608959. The reversal of 256608909 is 909806652.

256608909 is a `hidden beast` number, since 2 + 566 + 0 + 89 + 0 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 162945225 + 93663684 = 12765^2 + 9678^2 .

It is not a de Polignac number, because 256608909 - 2³ = 256608901 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256608901) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14256042 + ... + 14256059.

It is an arithmetic number, because the mean of its divisors is an integer number (61776221).

Almost surely, 2^256608909 is an apocalyptic number.

It is an amenable number.

256608909 is a deficient number, since it is larger than the sum of its proper divisors (114048417).

256608909 is a wasteful number, since it uses less digits than its factorization.

256608909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28512107 (or 28512104 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 256608909 is about 16019.0171046791. The cubic root of 256608909 is about 635.4634507054.

The spelling of 256608909 in words is "two hundred fifty-six million, six hundred eight thousand, nine hundred nine".