17 is a Fermat prime, which means that the 17-sided regular polygon (the heptadecagon) is constructible using compass and straightedge (as proved by Gauss).
17
See also
Constructible Polygon, Fermat Prime, Heptadecagon, Thomson CubicExplore with Wolfram|Alpha
References
Lefevre, V. "Properties of 17." http://www.vinc17.org/d17_eng.html.Cite this as:
Weisstein, Eric W. "17." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/17.html