logging into router issue

ok so, i travel a lot for work and passwords and memory are not apparently my strong suite. 

when i first got my service, i changed the admin password to login to HTTPS://192.168.0.1 

now i can not remember for the life of me what i changed it too, or if i actually changed it all. is it possible to change my router back to factory settings and it go back to admin and password.. or am i stuck with this issue ?