257666247 has 12 divisors (see below), whose sum is σ = 385018920. Its totient is φ = 165853968.

The previous prime is 257666243. The next prime is 257666273. The reversal of 257666247 is 742666752.

It is not a de Polignac number, because 257666247 - 2² = 257666243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257666243) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 493353 + ... + 493874.

It is an arithmetic number, because the mean of its divisors is an integer number (32084910).

Almost surely, 2^257666247 is an apocalyptic number.

257666247 is a deficient number, since it is larger than the sum of its proper divisors (127352673).

257666247 is a wasteful number, since it uses less digits than its factorization.

257666247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 987262 (or 987259 counting only the distinct ones).

The product of its digits is 846720, while the sum is 45.

The square root of 257666247 is about 16051.9857650074. The cubic root of 257666247 is about 636.3350480398.

The spelling of 257666247 in words is "two hundred fifty-seven million, six hundred sixty-six thousand, two hundred forty-seven".