How many pages are in Alfred Kropp?

"Alfred Kropp" is not a book, so it doesn't have any pages. It's likely you're thinking of a character from a book.

Are you thinking of "All Quiet on the Western Front" by Erich Maria Remarque?

If so, the book is about 240 pages long depending on the edition. The main character, Paul Bäumer, has a close friend named Stanislaus Katczinsky, nicknamed "Kat" who could be the "Alfred Kropp" you're thinking of.

Could you please clarify the name or the book you're referring to?