my $search_str = "...";
my @numbers    = (...);
foreach my $n (sort {length($b) <=> length($a)} 
               grep {length($_) <=  length($search_str)}
               @numbers) {
  if ($n eq substr($search_str,0,length $n)) {
    print "$n matched!\n";
    exit;
  }
}
print "No match!\n";