What programming language will enable me to enter a very long number without converting it to floating point?

Question

What would be the best way to do the following.

Enter a very long number, lets say 500,000 digits long without it going into scientific notation; and then am able to

Answer 1

What you're looking for isn't necessarily a language, but an arbitrary-precision library.

GMP would be a fast implementation in C/C++, and scripting languages that handles big integers would probably use something like that.