257997 has 4 divisors (see below), whose sum is σ = 344000. Its totient is φ = 171996.

The previous prime is 257993. The next prime is 258019. The reversal of 257997 is 799752.

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 not a de Polignac number, because 257997 - 2² = 257993 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 257997.

It is not an unprimeable number, because it can be changed into a prime (257993) 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, 42997 + ... + 43002.

It is an arithmetic number, because the mean of its divisors is an integer number (86000).

2²⁵⁷⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

257997 is a deficient number, since it is larger than the sum of its proper divisors (86003).

257997 is an equidigital number, since it uses as much as digits as its factorization.

257997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86002.

The product of its digits is 39690, while the sum is 39.

The square root of 257997 is about 507.9340508373. The cubic root of 257997 is about 63.6607208553.

The spelling of 257997 in words is "two hundred fifty-seven thousand, nine hundred ninety-seven".