257761643 has 2 divisors, whose sum is σ = 257761644. Its totient is φ = 257761642.

The previous prime is 257761639. The next prime is 257761697. The reversal of 257761643 is 346167752.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 257761643 - 2² = 257761639 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 257761643.

It is not a weakly prime, because it can be changed into another prime (257761043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128880821 + 128880822.

It is an arithmetic number, because the mean of its divisors is an integer number (128880822).

Almost surely, 2^257761643 is an apocalyptic number.

257761643 is a deficient number, since it is larger than the sum of its proper divisors (1).

257761643 is an equidigital number, since it uses as much as digits as its factorization.

257761643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 211680, while the sum is 41.

The square root of 257761643 is about 16054.9569603908. The cubic root of 257761643 is about 636.4135686441.

The spelling of 257761643 in words is "two hundred fifty-seven million, seven hundred sixty-one thousand, six hundred forty-three".