in reply to finding the correct integer

Obligatory link to What Every Programmer Should Know About Floating-Point Arithmetic and reference to bignum iff you don't mind the performance hit.

$ perl -wMstrict -Mbignum -le 'print int(0.6505 / 0.0001)'
6505

# Or, limit the scope of the pragma:

$ perl -wMstrict -le 'print do { use bignum; int(0.6505 / 0.0001) }'
6505

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In Section Seekers of Perl Wisdom