There seems to be some upper limit of about 300 digits

Actually, the limit is a lot smaller: as perl uses floating points to store its numbers, what you end up with is a big inaccurate number. the exact limits and accuracy are dependand.

If you want to know how perl stores numbers type:

perl -V
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To see the flags your perl interpreter was compiled with.

Find the line saying nvtype=' ... ' which is your system representation for perl numbers (usually double I guess). Also uselongdouble and uselongfloat if set to define might make your numbers more accurate.

You will have to decide for yourself if you care about the inaccuracies, if you do, see Math::Bigint and Math::Bigfloat as mentioned in the posts above.

Note: If you have a number stored in a string, it will only get converted when use them as numbers. So things like $big_number = '10231273879128749879857'; stay exact if you do not do arithmetics on them (and don't do things like $big_number == $other_number, use $big_number eq $other_number if you really need to).

-- 
Joost       downtime n. The period during which a system
            is error-free and immune from user input.
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