257642731 has 2 divisors, whose sum is σ = 257642732. Its totient is φ = 257642730.

The previous prime is 257642719. The next prime is 257642747. The reversal of 257642731 is 137246752.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 257642731 - 2⁹ = 257642219 is a prime.

It is a super-2 number, since 2×257642731² = 132759553674276722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (257642771) 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, 128821365 + 128821366.

It is an arithmetic number, because the mean of its divisors is an integer number (128821366).

Almost surely, 2^257642731 is an apocalyptic number.

257642731 is a deficient number, since it is larger than the sum of its proper divisors (1).

257642731 is an equidigital number, since it uses as much as digits as its factorization.

257642731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 70560, while the sum is 37.

The square root of 257642731 is about 16051.2532532510. The cubic root of 257642731 is about 636.3156890040.

The spelling of 257642731 in words is "two hundred fifty-seven million, six hundred forty-two thousand, seven hundred thirty-one".