Obviously, in order to answer this super-silly thought exercise, you’d have to make it a little bit more manageable to calculate. That means in this scenario, the Earth is perfectly round, has the same density all throughout, and won’t, like, scorch your bum when you fall through the core. Life Noggin explains the math behind how long it would take, giving consideration to all that gravity nonsense, and comes up with a shockingly small number.
It’s 42 minutes. Let’s start digging a hole.