The question: "why do hash functions use prime numbers?" I knew I'd seen someone suggest it wasn't necessary in researching this topic last week. (They cited this, if you care.)
The Google search: "prime hash".
Result #1: Why do hash functions use prime numbers?
Result #2: Prime Hanger Steak with Crispy Hash Browns and Pierre Poivre Sauce
I think it was lunchtime at that point.
Also, did you know the reproductive cycle of cicadas is 17 years?