I doubt it would make an SEO effect unless you think someone will be googling the term "page", but you could use str_replace() to replace the parameter in the url like:
<?php echo str_replace("pageNum_Properties=","page=",$Properties->getPrevPageLink()); ?>
Then on the top of the page change it back in the php above the recordset like:
<?php
if (isset($_GET["page"])) $_GET["pageNum_Properties"] = $_GET["page"];
?>