How can i find a phone number which i've vrote in the keypad(while on the phone with someone)

Hey guys, someone called me and i needed to write down a phone number, i pressed the Keypad button from the calling screen with that person and wrote down the number. After this he hang up. The phone number that i vrote down has gone.

Is there any History for this keypad or anything like that?

Where can i find that number now?