256560136705 has 4 divisors (see below), whose sum is σ = 307872164052. Its totient is φ = 205248109360.

The previous prime is 256560136667. The next prime is 256560136753. The reversal of 256560136705 is 507631065652.

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 104871697921 + 151688438784 = 323839^2 + 389472^2 .

It is not a de Polignac number, because 256560136705 - 2⁹ = 256560136193 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25656013666 + ... + 25656013675.

It is an arithmetic number, because the mean of its divisors is an integer number (76968041013).

Almost surely, 2^256560136705 is an apocalyptic number.

It is an amenable number.

256560136705 is a deficient number, since it is larger than the sum of its proper divisors (51312027347).

256560136705 is an equidigital number, since it uses as much as digits as its factorization.

256560136705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51312027346.

The product of its (nonzero) digits is 1134000, while the sum is 46.

The spelling of 256560136705 in words is "two hundred fifty-six billion, five hundred sixty million, one hundred thirty-six thousand, seven hundred five".