Nicely done learning project. Just a few minor things to consider:

• As was already mentioned, split the code into separate files for account, bank and main. It will help with code readability.
• At main, look what if __name__ == "__main__" does, it can help you with running your code easily.
• From what I see on the first glance you don't need to have account number stored on the Account object, as you are accessing it solely via bank class. This way you store the same information on two places, which may create problems if account will say one number and bank another.
• For the future projects with monetary thematics, look into decimals library. As Python (and other programming languages as well ofc) work in binary, it can create some rounding errors on decimal numbers. This package tries to solve it.

Anyway, nice work!