eval "require $class";

##</code><code>##

$class->mysub();

##</code><code>##

package pm_1175392::mymod123;

sub mysub { return 'In package: ' . __PACKAGE__; }

1;

##</code><code>##

#!/usr/bin/env perl -l

use strict;
use warnings;

my $modno = '123';
my $class = "pm_1175392::mymod$modno";
eval "require $class";

print $class->mysub();

##</code><code>##

$ ./pm_1175392_variable_name_mod.pl
In package: pm_1175392::mymod123
$