icosikaihena
1200 sided figure is chiliadihectagon
A 17 sided figure is a heptadecagon.
icosihenagon= 21-sided polygon icosihenagon= 21-sided polygon
Icosikaihenagon
Nonagon
it is a Dodecagon
octogon
hexagon
a pentagon.
Nonagon.
21
I would call it a 102-gon.