The Simple Math Behind the Mighty Roots of Unity
quantamagazine.org
quantamagazine.org
Wildberger's has a gentle introduction to this [0], though you'll have to tolerate his idiosyncratic notation ("polynumbers" instead of "polynomials")
A more sophisticated next step would be Richard Borcherd's video [1] on them as part of his series on Galois theory. Airdropping into the middle of that series might be a bit confusing, hopefully an enticement to watch the whole thing from the beginning, and well worth it since Galois theory is a historically important and rich vein of mathematics.