use warnings;
use strict;
use Data::Dumper;

push my @array, map { [ int( $_->[1] / 1_000_000 ), $_->[0] ] }
  sort { $a->[1] <=> $b->[1] }
  map { [ $_, ( split /\s+/, $_ )[4] ] } <DATA>;

print Dumper \@array;

__DATA__
0    50    4    46    723430    0    2    1    2    1    1    1    1    3    1
0    50    4    46    5533723430    0    2    1    2    1    1    1    1    3    1
0    50    4    46    33723430    0    2    1    2    1    1    1	1    3    1
0    50    2    48    654732    0    1    1    1    0    2    3    2	1    3


##</code><code>##

$VAR1 = [
          [
            0,
            '0    50    2    48    654732    0    1    1    1    0    2    3    2	1    3
'
          ],
          [
            0,
            '0    50    4    46    723430    0    2    1    2    1    1    1    1    3    1
'
          ],
          [
            33,
            '0    50    4    46    33723430    0    2    1    2    1    1    1	1    3    1
'
          ],
          [
            5533,
            '0    50    4    46    5533723430    0    2    1    2    1    1    1    1    3    1
'
          ]
        ];