257297217 has 4 divisors (see below), whose sum is σ = 343062960. Its totient is φ = 171531476.

The previous prime is 257297213. The next prime is 257297269. The reversal of 257297217 is 712792752.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 257297217 - 2² = 257297213 is a prime.

It is not an unprimeable number, because it can be changed into a prime (257297213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42882867 + ... + 42882872.

It is an arithmetic number, because the mean of its divisors is an integer number (85765740).

Almost surely, 2^257297217 is an apocalyptic number.

It is an amenable number.

257297217 is a deficient number, since it is larger than the sum of its proper divisors (85765743).

257297217 is an equidigital number, since it uses as much as digits as its factorization.

257297217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85765742.

The product of its digits is 123480, while the sum is 42.

The square root of 257297217 is about 16040.4868068273. The cubic root of 257297217 is about 636.0311162143.

The spelling of 257297217 in words is "two hundred fifty-seven million, two hundred ninety-seven thousand, two hundred seventeen".