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

In mathematics

199 is a centered triangular number.

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.

See also

• All pages with titles containing 199

References

1. Sloane, N. J. A. (ed.). "Sequence A005448 (Centered triangular numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
2. Sloane, N. J. A. (ed.). "Sequence A136162 (List of prime quadruplets)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
3. Sloane, N. J. A. (ed.). "Sequence A006050 (Smallest number of additive persistence n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.

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