perl -e '
for $j (1001,1_000_001,1_000_000_001) {
$i=$j**2;
print "\n",$j,": \t",$i,"\t=";
printf "%020lu", $i;
}'

1001: 	1002001	=00000000000001002001
1000001: 	1000002000001	=00000000004294967295
1000000001: 	1.000000002e+18	=00000000004294967295