<image>A diving team conducted an age survey of its athletes to understand their age distribution. Based on the ages of the divers (unit: years), the following statistical charts $$①$$ and $$②$$ were drawn. Please answer the following questions using the relevant information: 
 
$$(1)$$ The number of divers surveyed is ______, and the value of $$m$$ in chart $$①$$ is ______; 
$$(2)$$ Calculate the mean, mode, and median of the ages of this group of divers.