257993 has 2 divisors, whose sum is σ = 257994. Its totient is φ = 257992.

The previous prime is 257989. The next prime is 258019. The reversal of 257993 is 399752.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 153664 + 104329 = 392^2 + 323^2 .

It is a cyclic number.

It is not a de Polignac number, because 257993 - 2² = 257989 is a prime.

It is a Chen prime.

It is a zygodrome in base 3.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 257993.

It is not a weakly prime, because it can be changed into another prime (257903) 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, 128996 + 128997.

It is an arithmetic number, because the mean of its divisors is an integer number (128997).

2²⁵⁷⁹⁹³ is an apocalyptic number.

257993 is the 272-nd centered heptagonal number.

It is an amenable number.

257993 is a deficient number, since it is larger than the sum of its proper divisors (1).

257993 is an equidigital number, since it uses as much as digits as its factorization.

257993 is an odious number, because the sum of its binary digits is odd.

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

The square root of 257993 is about 507.9301133030. The cubic root of 257993 is about 63.6603918538.

The spelling of 257993 in words is "two hundred fifty-seven thousand, nine hundred ninety-three".