257730397 has 2 divisors, whose sum is σ = 257730398. Its totient is φ = 257730396.

The previous prime is 257730377. The next prime is 257730413. The reversal of 257730397 is 793037752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 256352121 + 1378276 = 16011^2 + 1174^2 .

It is a cyclic number.

It is not a de Polignac number, because 257730397 - 2¹⁹ = 257206109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257730367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128865198 + 128865199.

It is an arithmetic number, because the mean of its divisors is an integer number (128865199).

Almost surely, 2^257730397 is an apocalyptic number.

It is an amenable number.

257730397 is a deficient number, since it is larger than the sum of its proper divisors (1).

257730397 is an equidigital number, since it uses as much as digits as its factorization.

257730397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 277830, while the sum is 43.

The square root of 257730397 is about 16053.9838357960. The cubic root of 257730397 is about 636.3878521440.

The spelling of 257730397 in words is "two hundred fifty-seven million, seven hundred thirty thousand, three hundred ninety-seven".