256507133064517 has 2 divisors, whose sum is σ = 256507133064518. Its totient is φ = 256507133064516.

The previous prime is 256507133064361. The next prime is 256507133064661. The reversal of 256507133064517 is 715460331705652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172803407811841 + 83703725252676 = 13145471^2 + 9148974^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256507133064517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256507133065517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128253566532258 + 128253566532259.

It is an arithmetic number, because the mean of its divisors is an integer number (128253566532259).

Almost surely, 2^{256507133064517} is an apocalyptic number.

It is an amenable number.

256507133064517 is a deficient number, since it is larger than the sum of its proper divisors (1).

256507133064517 is an equidigital number, since it uses as much as digits as its factorization.

256507133064517 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15876000, while the sum is 55.

The spelling of 256507133064517 in words is "two hundred fifty-six trillion, five hundred seven billion, one hundred thirty-three million, sixty-four thousand, five hundred seventeen".