I think when you use a variable that can have values in the range of millions, it's prudent to use 64-bit types and not 32-bit unless you are very much memory-c

I think when you use a variable that can have values in the range of millions, it's prudent to use 64-bit types and not 32-bit unless you are very much memory-constrained. And I've never seen a 64-bit signed variable overflow.