Turn off 2 factor authentication for Mac book

My Mac book keeps reminding me to set up 2 factor authentication but it is asking me to put in the passcode for an apple phone that I used over 5 years ago. I have the phone but no idea what my passcode would have been back then ! Help ! Can I either turn off the two factor authentication or use another device ? My current phone number is added as a trusted phone number but do I need it to be added as a trusted device ? Help.