257320321 has 2 divisors, whose sum is σ = 257320322. Its totient is φ = 257320320.

The previous prime is 257320319. The next prime is 257320397. The reversal of 257320321 is 123023752.

257320321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 134908225 + 122412096 = 11615^2 + 11064^2 .

It is a cyclic number.

It is not a de Polignac number, because 257320321 - 2¹ = 257320319 is a prime.

Together with 257320319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (257320421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128660160 + 128660161.

It is an arithmetic number, because the mean of its divisors is an integer number (128660161).

Almost surely, 2^257320321 is an apocalyptic number.

It is an amenable number.

257320321 is a deficient number, since it is larger than the sum of its proper divisors (1).

257320321 is an equidigital number, since it uses as much as digits as its factorization.

257320321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 257320321 is about 16041.2069683051. The cubic root of 257320321 is about 636.0501531129.

The spelling of 257320321 in words is "two hundred fifty-seven million, three hundred twenty thousand, three hundred twenty-one".