You can also use bignum but there will be speed penalties. You could restrict the 'use bignum;' to the smallest possible scope to limit the number of places where you will be penalized. $ perl -Mbignum -le 'print 2**128' 340282366920938463463374607431768211456 You can also use Math::BigInt directly $ perl -MMath::BigInt -le 'my $n = (Math::BigInt->new(2))**128; print $n;' 340282366920938463463374607431768211456