Though there are many tools that deal with PDF files, there is a surprising scarcity of software which can extract the statistics of textual content in a PDF file. Especially, the number of words in a PDF file.
PractiCount and Invoice is a trialware tool that can be used to count the words in a PDF. Add all the files you want counted and press Count Statistics. The tool shows the number of words, characters and lines in the selected files.
Tried with: PractiCount and Invoice 3.2