I try to input a number 17 digits long. The whole number fits in the cell
just fine, but it cuts off the last 2 digits of the number and changes the
digits to "00." It doesn't matter what font size I use, how wide I make the
cell, or what format number type I use. I tried using custom, general,
number, etc.. all do the same thing, changes the last 2 digits to "00."

How do I fix it? Why will the cell accept unlimited number length, but only
accept numbers up to 15 digits? Why is everything past the 15th digit
automatically changed to "0"?