It's because number theory is ancient. The concept of primality is millennia old. The words used to describe numbers are thus built up over a very long time, an

It's because number theory is ancient. The concept of primality is millennia old. The words used to describe numbers are thus built up over a very long time, and often were meant to evoke imagery, concepts, or even personalities. If you examine younger branches of mathematics with fewer numbers, like topology or category theory, you will find more systematically-named rules and more systems named for people. The list of separation axioms [0] is the best-known example. [0] https://en.wikipedia.org/wiki/Separation_axiom https://en.wikipedia.org/wiki/Separation_axiom