In this task, you are given an input list A. You need to find all the elements of the list that are numbers and calculate their sum.
['z', 'e', '3819', 'P', 'A', 'D', '8853', '6837', '3741', '2387', '4825', '3909', 'x', '4317', '6647', 'B', '9925', '1625', 'B', 'e']