A few time TeamViewer has changed ID’s on me. (Not exactly sure why) But if you can get a command prompt on the machine you can get the ID out using the following query.

Apart from the calls, you can share presentations through TeamViewer. It is neither a straightforward application software nor a complicated one so if you’re new to it, don’t worry – you’ll get the hang of it. See also: How to transfer files on TeamViewer. On any video telephony platform, video calls are the most popular. I cloned a Mac and am getting identical TeamViewer IDs on both. Uninstalling (including deleting config files) on both systems and then reinstalling doesn't seem to be working in TeamViewer 12 (that,. See for yourself why millions of people around the world love using TeamViewer for remote access and remote control – download TeamViewer free for personal use. Download TeamViewer Free Try before you buy – experience the full power of TeamViewer. Get Teamviewer Client ID remotely from registry. If you need to find one of your TeamViewer client IDs on a local network, you can do it by remotely connecting to the client's registry.

What's My Teamviewer Id

How To Find Teamviewer Id

UPDATE: Get the latest version here that pulls back the ID for even the latest TeamViewer 13.

How To Get Teamviewer Id And Password

Copy the Hex Value and use a Hex to Decimal converter

There you have your TeamViewer ID.
(You are still have to know the password though, cant help you there)

*** Update 11/05/2017 ***
As pointed out by peter, looks like version 11 just uses the TeamViewer Key.