198095991 has 4 divisors (see below), whose sum is σ = 264127992. Its totient is φ = 132063992.

The previous prime is 198095971. The next prime is 198095999. The reversal of 198095991 is 199590891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199590891 = 3 ⋅66530297.

It is a cyclic number.

It is not a de Polignac number, because 198095991 - 2⁹ = 198095479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198095999) 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, 33015996 + ... + 33016001.

It is an arithmetic number, because the mean of its divisors is an integer number (66031998).

Almost surely, 2^198095991 is an apocalyptic number.

198095991 is a deficient number, since it is larger than the sum of its proper divisors (66032001).

198095991 is an equidigital number, since it uses as much as digits as its factorization.

198095991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66032000.

The product of its (nonzero) digits is 262440, while the sum is 51.

The square root of 198095991 is about 14074.6577578284. The cubic root of 198095991 is about 582.9418418802.

The spelling of 198095991 in words is "one hundred ninety-eight million, ninety-five thousand, nine hundred ninety-one".