256804688809 has 2 divisors, whose sum is σ = 256804688810. Its totient is φ = 256804688808.

The previous prime is 256804688761. The next prime is 256804688827. The reversal of 256804688809 is 908886408652.

256804688809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 209263247209 + 47541441600 = 457453^2 + 218040^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256804688809 is a prime.

It is not a weakly prime, because it can be changed into another prime (256804688869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128402344404 + 128402344405.

It is an arithmetic number, because the mean of its divisors is an integer number (128402344405).

Almost surely, 2^256804688809 is an apocalyptic number.

It is an amenable number.

256804688809 is a deficient number, since it is larger than the sum of its proper divisors (1).

256804688809 is an equidigital number, since it uses as much as digits as its factorization.

256804688809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 53084160, while the sum is 64.

The spelling of 256804688809 in words is "two hundred fifty-six billion, eight hundred four million, six hundred eighty-eight thousand, eight hundred nine".