Reminder To Call

I often find myhself at the end of the day, or on the week end, thinking: I need to call X and make a appointment, but I can't now it is outside of office hours. Then I'll forget about it during the day, or I won't be able to find the phone number easily and I'll put it off. What I would like is some kind of reminder system that has the ability to store a phone number and then I can just press a button to call them. Often this number won't be in my contacts as I won't expect to deal with them more than once. Ideally there would be away to do this will Google Now.