Can I turn off page numbering?

Yes.

To do this:

1. Click on Design.
2. Click on  Survey settings.
3. Under Completion options, untick Show survey progress bar.
4. Click Save.

This hides both the progress bar at the top of each page and the page numbers.

Page numbers will automatically be hidden if your survey contains routing – there is no need to hide the survey progress bar in a routed survey if you do not want to.