257231321 has 2 divisors, whose sum is σ = 257231322. Its totient is φ = 257231320.

The previous prime is 257231297. The next prime is 257231339. The reversal of 257231321 is 123132752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 240715225 + 16516096 = 15515^2 + 4064^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257231321 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (257239321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128615660 + 128615661.

It is an arithmetic number, because the mean of its divisors is an integer number (128615661).

Almost surely, 2^257231321 is an apocalyptic number.

It is an amenable number.

257231321 is a deficient number, since it is larger than the sum of its proper divisors (1).

257231321 is an equidigital number, since it uses as much as digits as its factorization.

257231321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2520, while the sum is 26.

The square root of 257231321 is about 16038.4326229217. The cubic root of 257231321 is about 635.9768139234.

The spelling of 257231321 in words is "two hundred fifty-seven million, two hundred thirty-one thousand, three hundred twenty-one".