How do I properly use Twig syntax in dynamic title/URL fields?
After chatting with The Honorable Brad Bell I learned that the sample tags in the field's label are showing some shorthand references to a few variables. (The {slug} reference for example.)

All I needed to do was use the object object to fully utilize twig tags/filters/etc. Here are a few ways to achieve what I was aiming for:

{% set num = (object.id * 1234567) | number_format(0, null, '-') %}documents/{{ num }}


or slightly more concise code:

documents/{{ (object.id * 1234567) | number_format(0, null, '-') }}


Also, thanks to carlsc for sharing the documentation on this feature. Reference: https://craftcms.com/docs/sections-and-entries#dynamic-entry-titles.

Happy Dynamic Titling and URLing.