First, remember that the volume of a cyliner is pi * (r^2) *h, but I think that could just be a typo in your entry.

Also keep in mind that a coin is NOT a perfect cylinder and the details in the design make the volume just slightly off when you do your calculations. As the numbers get bigger, the small error grows as well.
Anyway, if you have 650 coins that fit into there, then the volume of the hopper is equal to the 650 coins multiplied by the volume of one coin. Granted, the actual hopper will hold more due to those errors mentioned above in your assumptions, but that is the basic formula.
Volume Of US 5-Cent Coin * 650 = Volume of Coin Hopper.
Volume of Coin Hopper / Volume of Desired Coin = # Of Desired Coins It Can Hold.