To get the total number of pages, you can use CAM::PDF. PDF can also be used for finding version and pages, $pdf->Version, $pdf->Pages.

use CAM::PDF;

my $filename = $ARGV[0]; #get the filename from the user

my $pdf=PDF->new("$filename");

my $self = CAM::PDF->new("$filename"); #total no of pages

my $pages = $self->numPages();

print "\n\nTotal number of pages: $pages\n\n";

untested:
[download]