256753177520561 has 4 divisors (see below), whose sum is σ = 256853904544500. Its totient is φ = 256652450496624.

The previous prime is 256753177520533. The next prime is 256753177520563. The reversal of 256753177520561 is 165025771357652.

It is a happy number.

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 184094857240336 + 72658320280225 = 13568156^2 + 8523985^2 .

It is a cyclic number.

It is not a de Polignac number, because 256753177520561 - 2²⁶ = 256753110411697 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 256753177520494 and 256753177520503.

It is not an unprimeable number, because it can be changed into a prime (256753177520563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50363508146 + ... + 50363513243.

It is an arithmetic number, because the mean of its divisors is an integer number (64213476136125).

Almost surely, 2^{256753177520561} is an apocalyptic number.

It is an amenable number.

256753177520561 is a deficient number, since it is larger than the sum of its proper divisors (100727023939).

256753177520561 is a wasteful number, since it uses less digits than its factorization.

256753177520561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100727023938.

The product of its (nonzero) digits is 92610000, while the sum is 62.

The spelling of 256753177520561 in words is "two hundred fifty-six trillion, seven hundred fifty-three billion, one hundred seventy-seven million, five hundred twenty thousand, five hundred sixty-one".