I’ve got pi to 25 decimal places. But that’s not really much of a mathematical accomplishment; it’s simply memorization. I don’t begin to understand number theory or some of these concepts. To be fair, I’ve never looked into them much. But differential equations was as far as I have ever needed to go in math.
I memorized it about 55 years ago, I think. Funny how those things stick with you, because I certainly haven’t thought about it much since.