bigint (3perl)       - Transparent BigInteger support for Perl
Math::BigInt (3perl) - Arbitrary size integer/float math package
Math::BigInt::Calc (3perl) - Pure Perl module to support Math::BigInt
Math::BigInt::CalcEmu (3perl) - Emulate low-level math with BigInt code
Math::BigInt::FastCalc (3perl) - Math::BigInt::Calc with some XS for more speed