@MariaECHASA -
The following may be a trick you can use to determine the number of pages for that course.
go to a different course, and select the "import existing content " link from the home page.
for content type, select copy a Canvas course.
Find the course that has all the pages in it and select it.
Then check the box for "select specific content"
then click on import - you get a list of all the content in the course and in parentheses next to the type of item to import is the number of items in that category - you should see a heading for pages. so you should see pages(454) if you have 454 pages.
let me know if that works for you.
As a side note, I would go ahead and import just one item that you know about so that you don't have that select content option hanging around in the import content area - then just delete that one item from the course.
Ron
tagging @chriscas and @SusanNiemeyer