How to find out someone else's imei without third-party resources?

Question

Android

Hello, the bottom line is that a person recognized my phone’s imei through an application like tindr, but I didn’t give him any data, didn’t follow the links, didn’t download anything, we just chatted, and then he called me (as he confirmed the number found out via imei) like he works in a secret organization and all that, explain how this is possible? What means can, through ordinary chatting in a dating application chat, where he does not even contact the administration of the application, like the FSB officers, give out all sorts of phone numbers? or how could he get the phone number? the photo was not mine, nickname name and surname too