256500362721561 has 16 divisors (see below), whose sum is σ = 392114472741888. Its totient is φ = 146100344403600.

The previous prime is 256500362721527. The next prime is 256500362721613. The reversal of 256500362721561 is 165127263005652.

It is not a de Polignac number, because 256500362721561 - 2¹³ = 256500362713369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (256500362721061) 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 in 15 ways as a sum of consecutive naturals, for example, 19637136535 + ... + 19637149596.

It is an arithmetic number, because the mean of its divisors is an integer number (24507154546368).

Almost surely, 2^{256500362721561} is an apocalyptic number.

256500362721561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

256500362721561 is a deficient number, since it is larger than the sum of its proper divisors (135614110020327).

256500362721561 is a wasteful number, since it uses less digits than its factorization.

256500362721561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39274286452.

The product of its (nonzero) digits is 4536000, while the sum is 51.

The spelling of 256500362721561 in words is "two hundred fifty-six trillion, five hundred billion, three hundred sixty-two million, seven hundred twenty-one thousand, five hundred sixty-one".