257606991 has 12 divisors (see below), whose sum is σ = 374816832. Its totient is φ = 170483616.

The previous prime is 257606963. The next prime is 257607011. The reversal of 257606991 is 199606752.

It is a happy number.

It is not a de Polignac number, because 257606991 - 2¹⁴ = 257590607 is a prime.

It is a super-2 number, since 2×257606991² = 132722723624148162, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257606911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 103231 + ... + 105696.

It is an arithmetic number, because the mean of its divisors is an integer number (31234736).

Almost surely, 2^257606991 is an apocalyptic number.

257606991 is a deficient number, since it is larger than the sum of its proper divisors (117209841).

257606991 is a wasteful number, since it uses less digits than its factorization.

257606991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209070 (or 209067 counting only the distinct ones).

The product of its (nonzero) digits is 204120, while the sum is 45.

The square root of 257606991 is about 16050.1399059323. The cubic root of 257606991 is about 636.2862645703.

The spelling of 257606991 in words is "two hundred fifty-seven million, six hundred six thousand, nine hundred ninety-one".