The minimalist value of pi (unless you need a far better approximation to ensuring that someone lands safely on a distant planet, or that a computersystem is in good working conditions).
For most practical purposes involving the constantπ, you’d do fine with the quick-and-dirty value of 3.
The ultimate number, this number cannot be matched. It is the very workings of this universe, the foundation of life, the opening to eternal peace, joy and tranquility.