Router Login password requirements

I have apparently forgotten my password to log in to the router from the beginning www.routerlogin.net screen. For whatever reason, the recovery process doesn't work either, it just sends me into an endless loop of asking for my log in and password. My question is, without manually doing a factory reset, which will kill all of my settings, I am hoping someone knows what the password requirments are, so that it might trigger my memory  for the password I created. I.E. (# of special characters like @#!, or the # of CAPS, etc) I cannot find this information anywhere. Thank you in advance.