Welcome to the Make community!
That doesn’t look like a numeric ID.
To get the URN ID, use the API mentioned here Help with Tagging Organizations and People in LinkedIn Posts via Make.com - #4 by samliew
Hope this helps! Let me know if there are any further questions or issues.
— @samliew
P.S.: Investing some effort into the Make Academy will save you lots of time and frustration using Make.