To many, prime numbers are a useless concept studied in maths and soon forgotten about, having no impact on the rest of our lives. While they do have some applications in computing and encryption, primes never seem to crop up in day-to-day life, remaining as “special numbers” that aren’t all that special. However, once every seventeen years, prime numbers become very relevant very quickly to millions of people across America, as an unavoidable swarm of insects fills the sky for weeks on end, chirping collectively at up to 100 decibels. This year, 2021, like 2004 and many other years before it, pharaoh cicadas are breeding and smarming in their billions.