257421757 has 2 divisors, whose sum is σ = 257421758. Its totient is φ = 257421756.

The previous prime is 257421733. The next prime is 257421763. The reversal of 257421757 is 757124752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 140327716 + 117094041 = 11846^2 + 10821^2 .

It is a cyclic number.

It is not a de Polignac number, because 257421757 - 2¹¹ = 257419709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257421707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128710878 + 128710879.

It is an arithmetic number, because the mean of its divisors is an integer number (128710879).

Almost surely, 2^257421757 is an apocalyptic number.

It is an amenable number.

257421757 is a deficient number, since it is larger than the sum of its proper divisors (1).

257421757 is an equidigital number, since it uses as much as digits as its factorization.

257421757 is an evil number, because the sum of its binary digits is even.

The product of its digits is 137200, while the sum is 40.

The square root of 257421757 is about 16044.3683889395. The cubic root of 257421757 is about 636.1337193948.

The spelling of 257421757 in words is "two hundred fifty-seven million, four hundred twenty-one thousand, seven hundred fifty-seven".