257715247 has 2 divisors, whose sum is σ = 257715248. Its totient is φ = 257715246.

The previous prime is 257715239. The next prime is 257715251. The reversal of 257715247 is 742517752.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 257715247 - 2³ = 257715239 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257715277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128857623 + 128857624.

It is an arithmetic number, because the mean of its divisors is an integer number (128857624).

Almost surely, 2^257715247 is an apocalyptic number.

257715247 is a deficient number, since it is larger than the sum of its proper divisors (1).

257715247 is an equidigital number, since it uses as much as digits as its factorization.

257715247 is an odious number, because the sum of its binary digits is odd.

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

The square root of 257715247 is about 16053.5119833636. The cubic root of 257715247 is about 636.3753824406.

The spelling of 257715247 in words is "two hundred fifty-seven million, seven hundred fifteen thousand, two hundred forty-seven".