how can i retrieve IME number for my stolen ipad? system only showing last few digits

Only WiFi+Cellular models of iPad have an IMEI. WiFi Only models have no cellular capabilities or hardware - and as such do not have an IMEI.

You can find your device model and serial numbers, IMEI and other information from another device that is signed-in to iCloud with your AppleID:

Settings > [Your Name / AppleID] - scroll down to see your device list, then tap on the relevant item

Alternatively, this information can be found within your AppleID account information. Using a web browser from any computer:

https://appleid.apple.com

Navigate to the devices tab to find your device information.

if you mean IMEI number then if you have a wifi ipad then it don't have one only cellular devices have an IMEI nr

if it is a cellular ipad then

Find the serial number or IMEI on your iPhone, iPad, or iPod touch - Apple Support

one they don't seem to have on the list of ways then if you sync'd the ipad with itunes then you can go into itunes preferences and click on the dialogs device tab then the device back up items should show seriel nr and IMEI as tooltip