rewriterule ^questions/([0-9]+).* ...
Maybe you need the No Escape [NE] flag on the rule? Search for noescape in this page.
If you have an encoded forward slash in the URI, Apache returns an immediete 404. The error log will state:
[info] [client 184.108.40.206] found %2f (encoded '/') in URI (decoded='/question/1/'), returning 404
To work around this, add to your httpd.conf root or
And then your rewrite will work. Information from the Apache manual:
For more information, see: