199 (one hundred [and] ninety-nine) is the natural number following 198 and preceding 200.

It is a prime number and the fourth part of a prime quadruplet: 191, 193, 197, 199.

199 is the smallest natural number that takes more than two iterations to compute its digital root as a repeated digit sum: $${\displaystyle {\begin{aligned}199&\mapsto 1+9+9=19\\&\mapsto 1+9=10\\&\mapsto 1+0=1.\end{aligned}}}$$ Thus, its additive persistence is three, and it is the smallest number of persistence three.