I am pretty new to using the RewriteRule, so I am likely missing something obvious, but I have a PHP script that takes URL variables like this:
{baseurl}prop
At a quick glance, it appears that you forgot to include the dash in your regular expression and you included trailing slash. Use this instead:
RewriteRule ^properties/([0-9A-Za-z-]+)$ /properties.php?prop=$1
If you look at your rule ^properties/([0-9A-Za-z]+)/$
you see that it needs to end with a forward slash. You can either remove that or make it optional like ^properties/([0-9A-Za-z]+)/?$
.