199218191 has 2 divisors, whose sum is σ = 199218192. Its totient is φ = 199218190.

The previous prime is 199218179. The next prime is 199218247. The reversal of 199218191 is 191812991.

It is a weak prime.

It is an emirp because it is prime and its reverse (191812991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199218191 - 2⁶ = 199218127 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199218091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99609095 + 99609096.

It is an arithmetic number, because the mean of its divisors is an integer number (99609096).

Almost surely, 2^199218191 is an apocalyptic number.

199218191 is a deficient number, since it is larger than the sum of its proper divisors (1).

199218191 is an equidigital number, since it uses as much as digits as its factorization.

199218191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 41.

The square root of 199218191 is about 14114.4674359325. The cubic root of 199218191 is about 584.0405447784.

The spelling of 199218191 in words is "one hundred ninety-nine million, two hundred eighteen thousand, one hundred ninety-one".