You should not have Migrated the info to a new Mac.
With other devices set up an syncing it should have been the case of just adding the Apple ID
This should have caused pop ups on other devices saying what it was using.
And then they should have appeared on the Mac and accepting them would add the iPhone Number to the Mac.
IF that was what you did and it did not work put the iPhone in Airplane Mode for a few minutes (so it breaks with the server) then activate it again and the Mac should then get the pop once the iPhone has contact with the server again.
10:07 pm Wednesday; November 15, 2017
iMac 2.5Ghz i5 2011 (Sierra)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
iPhone 6 iOS 11.x and an iPad (2)