195891639197 has 2 divisors, whose sum is σ = 195891639198. Its totient is φ = 195891639196.

The previous prime is 195891639157. The next prime is 195891639221. The reversal of 195891639197 is 791936198591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 162204340516 + 33687298681 = 402746^2 + 183541^2 .

It is a cyclic number.

It is not a de Polignac number, because 195891639197 - 2⁸ = 195891638941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195891639157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97945819598 + 97945819599.

It is an arithmetic number, because the mean of its divisors is an integer number (97945819599).

Almost surely, 2^195891639197 is an apocalyptic number.

It is an amenable number.

195891639197 is a deficient number, since it is larger than the sum of its proper divisors (1).

195891639197 is an equidigital number, since it uses as much as digits as its factorization.

195891639197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33067440, while the sum is 68.

The spelling of 195891639197 in words is "one hundred ninety-five billion, eight hundred ninety-one million, six hundred thirty-nine thousand, one hundred ninety-seven".