257785531 has 2 divisors, whose sum is σ = 257785532. Its totient is φ = 257785530.

The previous prime is 257785519. The next prime is 257785537. The reversal of 257785531 is 135587752.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 257785531 - 2⁹ = 257785019 is a prime.

It is a super-2 number, since 2×257785531² = 132906759985903922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (257785537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128892765 + 128892766.

It is an arithmetic number, because the mean of its divisors is an integer number (128892766).

Almost surely, 2^257785531 is an apocalyptic number.

257785531 is a deficient number, since it is larger than the sum of its proper divisors (1).

257785531 is an equidigital number, since it uses as much as digits as its factorization.

257785531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 294000, while the sum is 43.

The square root of 257785531 is about 16055.7008878467. The cubic root of 257785531 is about 636.4332278630.

The spelling of 257785531 in words is "two hundred fifty-seven million, seven hundred eighty-five thousand, five hundred thirty-one".