11. Using 120 unit cubes, form a rectangular prism, and paint its entire surface. The maximum number of unit cubes that have only one face painted is $\qquad$ pieces

Constructing the above text in English, please retain the original text's line breaks and format, and output the translation result directly.
[Answer] 64
[Solution] Let the length, width, and height of the rectangular prism be $l, m, n$ (assuming $l \geq m \geq n$), it is easy to know that the small cubes with only one face painted can only be on each face. To maximize this number, then $n=2$ (otherwise, there would be too many small cubes inside that have no faces painted). Since $l m n=120 \Rightarrow l m=60$. At this point, the number of small cubes with only one face painted is $2(l-2)(m-2)=2(l m-2 l-2 m+4)=2(60-2 l-2 m+4)=2 \times 64-4(l+m)$. To maximize $2 \times 64-4(l+m)$, we need to minimize $l+m$. Considering $l m=60$, it is easy to see that when $l=10, m=6$, $l+m$ is minimized. Therefore, the maximum number of small cubes with only one face painted is $2 \times 64-4 \times(10+6)=64$.