257320397 has 2 divisors, whose sum is σ = 257320398. Its totient is φ = 257320396.

The previous prime is 257320321. The next prime is 257320421. The reversal of 257320397 is 793023752.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 155027401 + 102292996 = 12451^2 + 10114^2 .

It is a cyclic number.

It is not a de Polignac number, because 257320397 - 2¹⁶ = 257254861 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 257320397.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257320697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128660198 + 128660199.

It is an arithmetic number, because the mean of its divisors is an integer number (128660199).

Almost surely, 2^257320397 is an apocalyptic number.

It is an amenable number.

257320397 is a deficient number, since it is larger than the sum of its proper divisors (1).

257320397 is an equidigital number, since it uses as much as digits as its factorization.

257320397 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 79380, while the sum is 38.

The square root of 257320397 is about 16041.2093372040. The cubic root of 257320397 is about 636.0502157324.

The spelling of 257320397 in words is "two hundred fifty-seven million, three hundred twenty thousand, three hundred ninety-seven".