It is called 'Icosi-kai-hexa-gon'. (Icosi means 20, Kai means and, hexa means six and gon is the final suffix)
name of 4000 sided polygon
The name of a 200 sided polygon is dihectagon.
The name of a 600 sided polygon is Hexcosiagon.
The names of polygons with sides ranging from 21 to 30 are as follows: a 21-sided polygon is called a icosagon, a 22-sided polygon is a dicosagon, a 23-sided polygon is a tricosagon, a 24-sided polygon is a tetracosagon, a 25-sided polygon is a pentacosagon, a 26-sided polygon is a hexacosagon, a 27-sided polygon is a heptacosagon, a 28-sided polygon is an octacosagon, a 29-sided polygon is a nonacosagon, and a 30-sided polygon is a triacontagon.
there is no such thing as two-sided polygon.
A 26-gon
The name of a 12 sided polygon is Dodecagon.
A 8 sided polygon is called a octagon.
name of 4000 sided polygon
The name of a 10 sided polygon is Decagon.
The name of a 9 sided polygon is Nonagon.
The name of a 19 sided polygon is enneadecagon.
The name of a 17 sided polygon is Heptadecagon.
The name of a 15 sided polygon is Pentadecagon.
The name of a 7 sided polygon is Heptagon.
The name of a 8 sided polygon is Octagon.
The name of a 14 sided polygon is Tetradecagon.