256057672681 has 2 divisors, whose sum is σ = 256057672682. Its totient is φ = 256057672680.

The previous prime is 256057672667. The next prime is 256057672711. The reversal of 256057672681 is 186276750652.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 253164954025 + 2892718656 = 503155^2 + 53784^2 .

It is a cyclic number.

It is not a de Polignac number, because 256057672681 - 2¹⁵ = 256057639913 is a prime.

It is a super-2 number, since 2×256057672681² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (256057672081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128028836340 + 128028836341.

It is an arithmetic number, because the mean of its divisors is an integer number (128028836341).

Almost surely, 2^256057672681 is an apocalyptic number.

It is an amenable number.

256057672681 is a deficient number, since it is larger than the sum of its proper divisors (1).

256057672681 is an equidigital number, since it uses as much as digits as its factorization.

256057672681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8467200, while the sum is 55.

The spelling of 256057672681 in words is "two hundred fifty-six billion, fifty-seven million, six hundred seventy-two thousand, six hundred eighty-one".