Heptadeca

Heptadeca is a prefix meaning seventeen. It is derived from the Greek word "heptakaideka" which literally translates to "seven and ten". This prefix is used in various fields, most notably in chemistry, to denote the presence of seventeen atoms or units within a molecule or structure. For example, in organic chemistry, heptadecahedron refers to a polyhedron with seventeen faces. In the naming of long-chain fatty acids, a saturated fatty acid with seventeen carbon atoms is called heptadecanoic acid.

The number seventeen itself has some interesting properties. It is a prime number, meaning it is only divisible by 1 and itself. In geometry, a heptadecagon is a polygon with seventeen sides and seventeen angles. Constructing a regular heptadecagon using only a compass and straightedge is a notable achievement in mathematics, first demonstrated by Carl Friedrich Gauss in 1796. This discovery was significant as it proved that a regular polygon with a number of sides that is a Fermat prime can be constructed.