Hi there, first question on this board, hope someone can help! ^^

I'm doing a project for my math class involving very large numbers, but they're NOT supposed to be written in scientific notation, but in standard form instead. I noticed though that any number after the 16th digit is instead replaced with a zero. Kind of an annoying auto feature, seeing how I don't want those extra numbers rounded off like that. Is there a way to keep the original number? For example, 2^64 is supposed to be 18,446,744,073,709,551,616. That's the number I want displayed. Instead I get 18,446,744,073,709,600,000.

Thank you very much!