257847939691 has 2 divisors, whose sum is σ = 257847939692. Its totient is φ = 257847939690.

The previous prime is 257847939631. The next prime is 257847939697. The reversal of 257847939691 is 196939748752.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 257847939691 - 2⁹ = 257847939179 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 257847939691.

It is not a weakly prime, because it can be changed into another prime (257847939697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128923969845 + 128923969846.

It is an arithmetic number, because the mean of its divisors is an integer number (128923969846).

Almost surely, 2^257847939691 is an apocalyptic number.

257847939691 is a deficient number, since it is larger than the sum of its proper divisors (1).

257847939691 is an equidigital number, since it uses as much as digits as its factorization.

257847939691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 205752960, while the sum is 70.

The spelling of 257847939691 in words is "two hundred fifty-seven billion, eight hundred forty-seven million, nine hundred thirty-nine thousand, six hundred ninety-one".