Lots! The exact number depends on which translation, which size and which kind you have.
Around 80,000 different versions of the Bible are sold each year. There are 900 versions just in English, but you'll find versions in over 2,000 different languages. As well as the language, the style and font size will change the number of pages. Bibles range from small pocket Bibles to big study Bibles that have lots of extra pages for pictures, maps and explanations of scripture.
A Bible can therefore have anything between a few hundred to a few thousand pages, depending on which one you choose.
The last verse in the NIV translation of the Bible (Revelation 22:21) says, "The grace of the Lord Jesus be with God's people. Amen." So the last word is 'Amen'.
There are different translations of the Bible so the final verse may look slightly different, depending on which version you look at, but the last word is always the same.
(If you've been given a little red New Testament and Psalms Bible from the Gideons, it's worth noting that the book of Psalms is at the end - but Psalms is actually an Old Testament book, so it wouldn't be there normally.)