257861287 has 4 divisors (see below), whose sum is σ = 273029616. Its totient is φ = 242692960.

The previous prime is 257861281. The next prime is 257861297. The reversal of 257861287 is 782168752.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 257861287 - 2⁷ = 257861159 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257861281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7584139 + ... + 7584172.

It is an arithmetic number, because the mean of its divisors is an integer number (68257404).

Almost surely, 2^257861287 is an apocalyptic number.

257861287 is a deficient number, since it is larger than the sum of its proper divisors (15168329).

257861287 is a wasteful number, since it uses less digits than its factorization.

257861287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15168328.

The product of its digits is 376320, while the sum is 46.

The square root of 257861287 is about 16058.0598765853. The cubic root of 257861287 is about 636.4955651004.

The spelling of 257861287 in words is "two hundred fifty-seven million, eight hundred sixty-one thousand, two hundred eighty-seven".