257720539 has 2 divisors, whose sum is σ = 257720540. Its totient is φ = 257720538.

The previous prime is 257720531. The next prime is 257720549. The reversal of 257720539 is 935027752.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 257720539 - 2³ = 257720531 is a prime.

It is not a weakly prime, because it can be changed into another prime (257720531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128860269 + 128860270.

It is an arithmetic number, because the mean of its divisors is an integer number (128860270).

Almost surely, 2^257720539 is an apocalyptic number.

257720539 is a deficient number, since it is larger than the sum of its proper divisors (1).

257720539 is an equidigital number, since it uses as much as digits as its factorization.

257720539 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 132300, while the sum is 40.

The square root of 257720539 is about 16053.6768062647. The cubic root of 257720539 is about 636.3797382500.

The spelling of 257720539 in words is "two hundred fifty-seven million, seven hundred twenty thousand, five hundred thirty-nine".