There exists a number oddity with 3 different 4-digit numbers. One is 9801, where (98 + 01)^2 = 9801. It also works with 3025: (30+25)^2 = 3025.

What is the other number?

What is the smallest 6-digit number that would work?

(in other words, in a 6-digit number abcdef: abcdef=(abc+def)^2)