257399 has 2 divisors, whose sum is σ = 257400. Its totient is φ = 257398.

The previous prime is 257381. The next prime is 257401. The reversal of 257399 is 993752.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257399 is a prime.

Together with 257401, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128699 + 128700.

It is an arithmetic number, because the mean of its divisors is an integer number (128700).

2²⁵⁷³⁹⁹ is an apocalyptic number.

257399 is a deficient number, since it is larger than the sum of its proper divisors (1).

257399 is an equidigital number, since it uses as much as digits as its factorization.

257399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17010, while the sum is 35.

The square root of 257399 is about 507.3450502370. The cubic root of 257399 is about 63.6114973347.

It can be divided in two parts, 257 and 399, that added together give a palindrome (656).

The spelling of 257399 in words is "two hundred fifty-seven thousand, three hundred ninety-nine".