use strict;
use warnings;

my @array = qw(2aa 2ba 12kf 9cn 9vn 21sg);
my @sorted = 
   map  { join('',@$_) }
   sort { $b->[0] <=> $a->[0] or $a->[1] cmp $b->[1] } 
   map  { /(\d+)(\w+)/;[$1,$2] } @array
;
print "$_\n" foreach @sorted;

__END__
21sg
12kf
9cn
9vn
2aa
2ba

##</code><code>##

map  { [/(\d+)(\w+)/] } @array