256809101915 has 16 divisors (see below), whose sum is σ = 314945072640. Its totient is φ = 200937218400.

The previous prime is 256809101911. The next prime is 256809101933. The reversal of 256809101915 is 519101908652.

It is a happy number.

It is not a de Polignac number, because 256809101915 - 2² = 256809101911 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a self number, because there is not a number n which added to its sum of digits gives 256809101915.

It is not an unprimeable number, because it can be changed into a prime (256809101911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35585 + ... + 717554.

It is an arithmetic number, because the mean of its divisors is an integer number (19684067040).

Almost surely, 2^256809101915 is an apocalyptic number.

256809101915 is a deficient number, since it is larger than the sum of its proper divisors (58135970725).

256809101915 is a wasteful number, since it uses less digits than its factorization.

256809101915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 754642.

The product of its (nonzero) digits is 194400, while the sum is 47.

The spelling of 256809101915 in words is "two hundred fifty-six billion, eight hundred nine million, one hundred one thousand, nine hundred fifteen".