Don't try to do this in Acrobat. There are many file renaming utilities out there that can do it for you, easily and quickly, once the files have been created and saved using the default names.
You don't need code to do this. Scan the documents or merge your images into a single PDF. Then use the "Split Pages" feature to split the pages into multiple one page documents. Use the output options to generate the numeric naming you need.
Among the various renaming options available we have one which can do the job while scanning.
While Scanning chose Output Option: "Save Multiple files" and Under its settings you can define the number of pages for each file, by default its just one.
Also check the prompt for more pages option if you scan page one by one.
Also share the information:
1) Acrobat build version
2) Operating system you are using
3) Scanner type FLATBED/ADF
ADF scanners can take in multiple pages and scan them automatically.