256366121365 has 4 divisors (see below), whose sum is σ = 307639345644. Its totient is φ = 205092897088.

The previous prime is 256366121359. The next prime is 256366121387. The reversal of 256366121365 is 563121663652.

256366121365 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 197098705764 + 59267415601 = 443958^2 + 243449^2 .

It is a cyclic number.

It is not a de Polignac number, because 256366121365 - 2⁹ = 256366120853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 25636612132 + ... + 25636612141.

It is an arithmetic number, because the mean of its divisors is an integer number (76909836411).

Almost surely, 2^256366121365 is an apocalyptic number.

It is an amenable number.

256366121365 is a deficient number, since it is larger than the sum of its proper divisors (51273224279).

256366121365 is an equidigital number, since it uses as much as digits as its factorization.

256366121365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51273224278.

The product of its digits is 1166400, while the sum is 46.

The spelling of 256366121365 in words is "two hundred fifty-six billion, three hundred sixty-six million, one hundred twenty-one thousand, three hundred sixty-five".