The number of X-Men comic books is quite large and constantly changing. Over the years, Marvel has released numerous series and one-shots related to X-Men. It's impossible to provide a precise count.
There are a ton of X-Men comic books. The franchise has been around for a long time and has had many ongoing series, limited series, and one-shots. So, it's impossible to give a precise count, but it's in the multiple thousands.
The 'Chamber X Men' comic is known for its engaging plot and detailed art. It offers a unique take on the superhero genre, with plenty of action and character development.
I have no idea. There's no obvious or common link between 7 15 and X-Men comics. Maybe it's a code or reference within a very niche aspect of X-Men lore that isn't widely known.
The X-Men Black comic was indeed cancelled. It could be due to a combination of factors such as changes in the comic market, reader preferences, or editorial directions within the publishing house.