Fifty stands for all that is holy. It also represents joy and celebration. Alternatively, the dream represents your fair share of something, as in 50:50.
To dream of the number 50 represents change in your life that is causing conflict. You may be struggling to deal with a change, having difficulty adjusting, or finally being forced to confront something you don't want to. Change that you feel you can't do anything about. Forced change or change you have to put up with.
Positively, the number 50 may represent feelings about having to do something different that doesn't feel special or important.
Negatively, the number 50 may represent feelings about a change being a little bit dangerous or risky. Not wanting to waste a new opportunity. Feeling that you are growing up.