11. Several people completed the task of planting 2013 trees, with each person planting the same number of trees. If 5 people did not participate in planting, the rest would need to plant 2 more trees each to fail to complete the task, while planting 3 more trees each would result in exceeding the task. How many people participated in planting?
Analysis: $2013=3 \times 11 \times 61=1 \times 2013=3 \times 671=11 \times 183=33 \times 61$
Quickly check $(2013-5) \times(1+2)>2013$
$$
\begin{array}{ll}
(671-5) \times(3+2)>2013 & \\
(11-5) \times(183+2)2013 ; & (11+3) \times(183-5)>2013 \\
(33+2) \times(61-5)2013 \\
(33-5) \times(61+2)2013$, so the answer is 61 people
Solution 2: Originally there were $x$ people planting trees, each planting $y$ trees.
$$
\begin{array}{l}
x y=2013, \\
(x-5) \quad(y+2)2013 \\
x y-5 y+2 x-102013
\end{array}
$$

That is $5 y-2 x+10>0 \quad 3 x-5 y-15>0, x$, $y$ in pairs, there are the following cases $(1,2013),(3,671),(11,183)$, $(33,61), y$ and $x$ can be swapped,
Substituting and checking, $(33,61)$ works, and the number of people is 61.