9514 1404 393
Answer:
4^4·6^5·7^7 = 1,639,390,814,208
Step-by-step explanation:
Taking the cube root multiplies each exponent by 1/3.
((4^12)(6^15)(7^21))^(1/3) = (4^(12/3))·(6^(15/3))·(7^(21/3)) = (4^4)(6^5)(7^7)