You have already been outdone by the gogolplex and graham's number.
I'm going for a googolplex^4 googolplexi * graham's number
Also, the whole "approximating at pi" thing is rubbish. Pi isn't "round". It's a constant ffs.
Holy crap learn your basic geometrical constants. 3.14159265
Now I'm going to the zoo. -indignant-