Most mathematicians would refer to it as a 666-gon.
If someone wanted to be pretentious, or unhelpful, they could call it a hexahectahexacontakaihexagon.
hexcosiahexacontakaihexagram
it is called a seven sided shape in Canada
A 90 sided shape is called Enneacontagon.
A 128-sided shape is called a hecatoicosioctagon.
An five sided shape is called a Pentagon
hexcosiahexacontakaihexagram
it is called a seven sided shape in Canada
The 22 sided shape is called a: ICOSIKAIDIGON
A 90 sided shape is called Enneacontagon.
Hommasquabblelagagon
A five-sided shape is called a pentagon.
a 4 sided shape is called a quadrilateral
A seven sided shape is called a heptagon.
A 128-sided shape is called a hecatoicosioctagon.
A 10-sided shape is called a decagon.
An five sided shape is called a Pentagon
The name "666-sided polygon" works just fine in this case.