257645369 has 2 divisors, whose sum is σ = 257645370. Its totient is φ = 257645368.

The previous prime is 257645357. The next prime is 257645383. The reversal of 257645369 is 963546752.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 148547344 + 109098025 = 12188^2 + 10445^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257645369 is a prime.

It is a super-3 number, since 3×257645369³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (257645329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128822684 + 128822685.

It is an arithmetic number, because the mean of its divisors is an integer number (128822685).

Almost surely, 2^257645369 is an apocalyptic number.

It is an amenable number.

257645369 is a deficient number, since it is larger than the sum of its proper divisors (1).

257645369 is an equidigital number, since it uses as much as digits as its factorization.

257645369 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1360800, while the sum is 47.

The square root of 257645369 is about 16051.3354273095. The cubic root of 257645369 is about 636.3178607388.

The spelling of 257645369 in words is "two hundred fifty-seven million, six hundred forty-five thousand, three hundred sixty-nine".