195891639257 has 2 divisors, whose sum is σ = 195891639258. Its totient is φ = 195891639256.

The previous prime is 195891639253. The next prime is 195891639269. The reversal of 195891639257 is 752936198591.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98284758016 + 97606881241 = 313504^2 + 312421^2 .

It is a cyclic number.

It is not a de Polignac number, because 195891639257 - 2² = 195891639253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 195891639193 and 195891639202.

It is not a weakly prime, because it can be changed into another prime (195891639253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97945819628 + 97945819629.

It is an arithmetic number, because the mean of its divisors is an integer number (97945819629).

Almost surely, 2^195891639257 is an apocalyptic number.

It is an amenable number.

195891639257 is a deficient number, since it is larger than the sum of its proper divisors (1).

195891639257 is an equidigital number, since it uses as much as digits as its factorization.

195891639257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36741600, while the sum is 65.

The spelling of 195891639257 in words is "one hundred ninety-five billion, eight hundred ninety-one million, six hundred thirty-nine thousand, two hundred fifty-seven".