256753056251561 has 2 divisors, whose sum is σ = 256753056251562. Its totient is φ = 256753056251560.

The previous prime is 256753056251543. The next prime is 256753056251569. The reversal of 256753056251561 is 165152650357652.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 167417591610025 + 89335464641536 = 12938995^2 + 9451744^2 .

It is a cyclic number.

It is not a de Polignac number, because 256753056251561 - 2²⁶ = 256752989142697 is a prime.

It is a super-2 number, since 2×256753056251561² (a number of 30 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 256753056251561.

It is not a weakly prime, because it can be changed into another prime (256753056251569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128376528125780 + 128376528125781.

It is an arithmetic number, because the mean of its divisors is an integer number (128376528125781).

Almost surely, 2^{256753056251561} is an apocalyptic number.

It is an amenable number.

256753056251561 is a deficient number, since it is larger than the sum of its proper divisors (1).

256753056251561 is an equidigital number, since it uses as much as digits as its factorization.

256753056251561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56700000, while the sum is 59.

The spelling of 256753056251561 in words is "two hundred fifty-six trillion, seven hundred fifty-three billion, fifty-six million, two hundred fifty-one thousand, five hundred sixty-one".