$6^{-1.4} \approx \square$ (Round to three decimal places as needed.)

Step 1 ：The question is asking for the value of \(6^{-1.4}\) rounded to three decimal places. This is a straightforward calculation that can be done using a calculator.

Step 2 ：The result is approximately 0.081.

Step 3 ：Final Answer: \(\boxed{0.081}\)