Identify the last two digits of the given number:
98765432
Let L2D(K) denote the 2 last digit of a number K
CLEARLY L2D(5^ anynumberover1)=25
L2D(6^25)=76 (.... LIKE L2D(6^5)......)
L2D(7^76)=01 (..... LIKE L2D(7^0)....)
L2D(8^1)=8
L2D(9^8)=21
21, the lucky number is the answer, IF I did not err...