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

Perl, Python, Ruby, and Java can all do that. External libraries exist for everything else.

I rather like Ruby and Python because they automatically switch from Fixnum to Bignum. (Python: int to long.)