257720417 has 2 divisors, whose sum is σ = 257720418. Its totient is φ = 257720416.

The previous prime is 257720401. The next prime is 257720423. The reversal of 257720417 is 714027752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188348176 + 69372241 = 13724^2 + 8329^2 .

It is a cyclic number.

It is not a de Polignac number, because 257720417 - 2⁴ = 257720401 is a prime.

It is not a weakly prime, because it can be changed into another prime (257720917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128860208 + 128860209.

It is an arithmetic number, because the mean of its divisors is an integer number (128860209).

Almost surely, 2^257720417 is an apocalyptic number.

It is an amenable number.

257720417 is a deficient number, since it is larger than the sum of its proper divisors (1).

257720417 is an equidigital number, since it uses as much as digits as its factorization.

257720417 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27440, while the sum is 35.

The square root of 257720417 is about 16053.6730065116. The cubic root of 257720417 is about 636.3796378333.

The spelling of 257720417 in words is "two hundred fifty-seven million, seven hundred twenty thousand, four hundred seventeen".