257660287 has 2 divisors, whose sum is σ = 257660288. Its totient is φ = 257660286.

The previous prime is 257660239. The next prime is 257660309. The reversal of 257660287 is 782066752.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 257660287 - 2²³ = 249271679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257660987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128830143 + 128830144.

It is an arithmetic number, because the mean of its divisors is an integer number (128830144).

Almost surely, 2^257660287 is an apocalyptic number.

257660287 is a deficient number, since it is larger than the sum of its proper divisors (1).

257660287 is an equidigital number, since it uses as much as digits as its factorization.

257660287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 282240, while the sum is 43.

The square root of 257660287 is about 16051.8001171208. The cubic root of 257660287 is about 636.3301417108.

The spelling of 257660287 in words is "two hundred fifty-seven million, six hundred sixty thousand, two hundred eighty-seven".