#!/usr/bin/perl
#

$num = 129;

$str = unpack("B32", pack("N", $num));
$str =~ s/^0+(?=\d)//;   # otherwise you'll get leading zeros
print "$str\n";

$fragment =  substr $str, 0, 5; #first 5 bytes
print "$fragment\n";
$num1=unpack("N", pack("B32", substr("0" x 32 . $fragment, -32)));
print "num1=$num1\n";

$fragment =  substr $str, 5, 3; #first 5 bytes
print "$fragment\n";
$num2=unpack("N", pack("B32", substr("0" x 32 . $fragment, -32)));
print "num2=$num2\n";