Solution 1

Note that A = 1. If A > 1, then . So D = 9. Therefore, B = 0. We have , this means that C = 8. So we have .

Solution 2

Since 4 is even, A is an even number. If A > 2, then . So A can only be 2. Then D = 8 or 9. Since , but A = 2 is the unit digit of . So D = 8 as . Now, we have . So B = 0 or 1. If B = 0, unit digit of , which is odd and is impossible. So B = 1.  or , which means that C = 2 (rejected as A = 2) or C = 7. Therefore the answer is .