Determine all possible 7-digit decimal (base 10) perfect square(s), each of whose digits is * nonzero* and *even*.

__Note__: While a solution is trivial with the aid of a computer program, show how to derive it without one.

(In reply to

solution by Dej Mar)

....As the final digit must be non-zero and even, D must be 2 or 8; and the 10^{0}-digit digit must be 4

**Why not 4 or 6??**