256177861717 has 2 divisors, whose sum is σ = 256177861718. Its totient is φ = 256177861716.

The previous prime is 256177861679. The next prime is 256177861729. The reversal of 256177861717 is 717168771652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 249849022801 + 6328838916 = 499849^2 + 79554^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256177861717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256177861747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128088930858 + 128088930859.

It is an arithmetic number, because the mean of its divisors is an integer number (128088930859).

Almost surely, 2^256177861717 is an apocalyptic number.

It is an amenable number.

256177861717 is a deficient number, since it is larger than the sum of its proper divisors (1).

256177861717 is an equidigital number, since it uses as much as digits as its factorization.

256177861717 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6914880, while the sum is 58.

The spelling of 256177861717 in words is "two hundred fifty-six billion, one hundred seventy-seven million, eight hundred sixty-one thousand, seven hundred seventeen".