What are the single digits of the 999 power of 999 and the 2007 power of 2007

What are the single digits of the 999 power of 999 and the 2007 power of 2007

9×9=81
1×9=9
For the n-th power of 999, starting from the 1-th power of 9, the single digit is cycled by 9,1,9,1. That is, when n is odd, the single digit is 9, and when n is even, the single digit is 1.999, the 999 th power and the single digit is 9
7×7=49
9×7=63
3×7=21
1×7=7
For the nth power of 2007, starting from the 1st power of 2007, the single digits are cycled by 7,9,3,1, once every 4 cycles
2007 / 4 = 401 + 32007, the number of the power of 2007 is 3