2 may be the only even prime - that is it’s the only prime divisible by 2 - but 3 is the only prime divisible by 3 and 5 is the only prime divisible by 5, so I fail to see how this is unique.

Exactly, “even” litterally means divisible by 2. We could easily come up with a term for divisible by 3 or 5. Maybe there even is one I’m not familiar with. So yeah 2 is nothing special.

“Threven” has a nice ring to it now that I think of it.