257520817 has 2 divisors, whose sum is σ = 257520818. Its totient is φ = 257520816.

The previous prime is 257520779. The next prime is 257520829. The reversal of 257520817 is 718025752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 183629601 + 73891216 = 13551^2 + 8596^2 .

It is a cyclic number.

It is not a de Polignac number, because 257520817 - 2¹⁹ = 256996529 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (257520017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128760408 + 128760409.

It is an arithmetic number, because the mean of its divisors is an integer number (128760409).

Almost surely, 2^257520817 is an apocalyptic number.

It is an amenable number.

257520817 is a deficient number, since it is larger than the sum of its proper divisors (1).

257520817 is an equidigital number, since it uses as much as digits as its factorization.

257520817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 39200, while the sum is 37.

The square root of 257520817 is about 16047.4551565038. The cubic root of 257520817 is about 636.2153070658.

The spelling of 257520817 in words is "two hundred fifty-seven million, five hundred twenty thousand, eight hundred seventeen".