198920191 has 4 divisors (see below), whose sum is σ = 199131192. Its totient is φ = 198709192.

The previous prime is 198920167. The next prime is 198920209. The reversal of 198920191 is 191029891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 191029891 = 13 ⋅14694607.

It is a cyclic number.

It is not a de Polignac number, because 198920191 - 2¹¹ = 198918143 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198923191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104080 + ... + 105973.

It is an arithmetic number, because the mean of its divisors is an integer number (49782798).

Almost surely, 2^198920191 is an apocalyptic number.

198920191 is a deficient number, since it is larger than the sum of its proper divisors (211001).

198920191 is an equidigital number, since it uses as much as digits as its factorization.

198920191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211000.

The product of its (nonzero) digits is 11664, while the sum is 40.

The square root of 198920191 is about 14103.9069409862. The cubic root of 198920191 is about 583.7491876241.

The spelling of 198920191 in words is "one hundred ninety-eight million, nine hundred twenty thousand, one hundred ninety-one".