195166991 has 2 divisors, whose sum is σ = 195166992. Its totient is φ = 195166990.

The previous prime is 195166973. The next prime is 195166997. The reversal of 195166991 is 199661591.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 195166991 - 2⁶ = 195166927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195166997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97583495 + 97583496.

It is an arithmetic number, because the mean of its divisors is an integer number (97583496).

Almost surely, 2^195166991 is an apocalyptic number.

195166991 is a deficient number, since it is larger than the sum of its proper divisors (1).

195166991 is an equidigital number, since it uses as much as digits as its factorization.

195166991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 131220, while the sum is 47.

The square root of 195166991 is about 13970.2180011623. The cubic root of 195166991 is about 580.0544845764.

The spelling of 195166991 in words is "one hundred ninety-five million, one hundred sixty-six thousand, nine hundred ninety-one".