257639 has 2 divisors, whose sum is σ = 257640. Its totient is φ = 257638.

The previous prime is 257627. The next prime is 257657. The reversal of 257639 is 936752.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 257639 - 2¹² = 253543 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

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 257639.

It is not a weakly prime, because it can be changed into another prime (257689) 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 as a sum of consecutive naturals, namely, 128819 + 128820.

It is an arithmetic number, because the mean of its divisors is an integer number (128820).

2²⁵⁷⁶³⁹ is an apocalyptic number.

257639 is a deficient number, since it is larger than the sum of its proper divisors (1).

257639 is an equidigital number, since it uses as much as digits as its factorization.

257639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11340, while the sum is 32.

The square root of 257639 is about 507.5815205462. The cubic root of 257639 is about 63.6312617431.

The spelling of 257639 in words is "two hundred fifty-seven thousand, six hundred thirty-nine".