256659868517449 has 2 divisors, whose sum is σ = 256659868517450. Its totient is φ = 256659868517448.

The previous prime is 256659868517407. The next prime is 256659868517453. The reversal of 256659868517449 is 944715868956652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 216990429054025 + 39669439463424 = 14730595^2 + 6298368^2 .

It is a cyclic number.

It is not a de Polignac number, because 256659868517449 - 2¹⁷ = 256659868386377 is a prime.

It is not a weakly prime, because it can be changed into another prime (256659868517149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128329934258724 + 128329934258725.

It is an arithmetic number, because the mean of its divisors is an integer number (128329934258725).

Almost surely, 2^{256659868517449} is an apocalyptic number.

It is an amenable number.

256659868517449 is a deficient number, since it is larger than the sum of its proper divisors (1).

256659868517449 is an equidigital number, since it uses as much as digits as its factorization.

256659868517449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31352832000, while the sum is 85.

The spelling of 256659868517449 in words is "two hundred fifty-six trillion, six hundred fifty-nine billion, eight hundred sixty-eight million, five hundred seventeen thousand, four hundred forty-nine".