191390197 has 2 divisors, whose sum is σ = 191390198. Its totient is φ = 191390196.

The previous prime is 191390191. The next prime is 191390207. The reversal of 191390197 is 791093191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 191296561 + 93636 = 13831^2 + 306^2 .

It is a cyclic number.

It is not a de Polignac number, because 191390197 - 2³ = 191390189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191390191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95695098 + 95695099.

It is an arithmetic number, because the mean of its divisors is an integer number (95695099).

Almost surely, 2^191390197 is an apocalyptic number.

It is an amenable number.

191390197 is a deficient number, since it is larger than the sum of its proper divisors (1).

191390197 is an equidigital number, since it uses as much as digits as its factorization.

191390197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15309, while the sum is 40.

The square root of 191390197 is about 13834.3845905772. The cubic root of 191390197 is about 576.2884247461.

The spelling of 191390197 in words is "one hundred ninety-one million, three hundred ninety thousand, one hundred ninety-seven".