Answer:
4,398,046,510,000 or 4^21
Step-by-step explanation:
If you need to solve:
(4^3)^7
4^3= 64
64^7= 4.39804651×10^12 or 4,398,046,510,000
If you just need the exponents answer:
You multiply exponents so the answer would be 4^21
