199998091 has 4 divisors (see below), whose sum is σ = 200357712. Its totient is φ = 199638472.

The previous prime is 199998089. The next prime is 199998107. The reversal of 199998091 is 190899991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 199998091 - 2¹ = 199998089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199998791) 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, 178975 + ... + 180088.

It is an arithmetic number, because the mean of its divisors is an integer number (50089428).

Almost surely, 2^199998091 is an apocalyptic number.

199998091 is a deficient number, since it is larger than the sum of its proper divisors (359621).

199998091 is an equidigital number, since it uses as much as digits as its factorization.

199998091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359620.

The product of its (nonzero) digits is 472392, while the sum is 55.

The square root of 199998091 is about 14142.0681302276. The cubic root of 199998091 is about 584.8016869867.

The spelling of 199998091 in words is "one hundred ninety-nine million, nine hundred ninety-eight thousand, ninety-one".