256164213517 has 2 divisors, whose sum is σ = 256164213518. Its totient is φ = 256164213516.

The previous prime is 256164213511. The next prime is 256164213521. The reversal of 256164213517 is 715312461652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 254546484676 + 1617728841 = 504526^2 + 40221^2 .

It is a cyclic number.

It is not a de Polignac number, because 256164213517 - 2³ = 256164213509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256164213511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128082106758 + 128082106759.

It is an arithmetic number, because the mean of its divisors is an integer number (128082106759).

Almost surely, 2^256164213517 is an apocalyptic number.

It is an amenable number.

256164213517 is a deficient number, since it is larger than the sum of its proper divisors (1).

256164213517 is an equidigital number, since it uses as much as digits as its factorization.

256164213517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 302400, while the sum is 43.

The spelling of 256164213517 in words is "two hundred fifty-six billion, one hundred sixty-four million, two hundred thirteen thousand, five hundred seventeen".