Erdem Bulut Hi!
I'll try to answer your questions:
1) Yes, your card number is on the back.
2) If you change your name, then I guess you should order a new card. A Metal Card is free if you pay 12 month up front for the Easy Green or Pack subscription, or 24 months for Easy Money. Otherwise the card will cost you €129 (so replacing the card is also €129).
This is what the back of the card looks like: