perl -e '
for $j (1000,1_000_000,1_000_000_000) {
$i=$j**2;
print "\n",$j,": \t",$i,"\t=";
printf "%020llu", $i;
}'

1000: 	1000000	=00000000000001000000
1000000: 	1000000000000	=00000000004294967295
1000000000: 	1e+18	=00000000004294967295