Happy Birthday Muttl

So before we congratulate to a very special person here a little riddle. I have posted some hints so you can determine how old the person in this case my loved mother is right now.

• The atomic number of tin
• The fifth magic number in physics
• The traditional number of years in a default jubilee period.
• The number of states in the USA (since 1959, still true in 2004).
• A calibre of ammunition (0.50 inches: see .50 BMG)
• In millimeters, the focal length of the normal lens in 35mm photography.
• the percentage equivalent to one half, so that the phrase "fifty-fifty" commonly expresses something divided equally in half, or an event of probability one half
• In years of marriage, the gold or "golden" wedding anniversary.

It is the smallest number that can be written as the sum of two squares in two distinct ways: It is also the sum of three squares.

These are enough hints. So make your guess.
(You can discuss your ideas in the comment field)

My dear Muttl,
I thank you for being what you are. You contribute a lot to keep the family together. By doing so I sometimes feel that you forget yourself a bit and care and worry more about others. For the next years I wish that take also time for yourself. Leave things a bit more out of your hand. Do things you would like to do and stand a bit more up for yourself. Even if this means given Popsch a harder time than he is used too. Both of you know what they mean to each other and you both should know what you mean to us. What you both have showed me is that no matter what physical distance is in between, it will not affect our relationsship but raises our own awareness to care for the other. I wish you have a nice time hiking in the mountains celbrating and relaxing.
With lot's of love
Andre