Please add a digit number in PDF numbering option. Per example: 1 could be 0001 (4 digits)... then 11 could be 0011, then 111, could be 0111 and later 1111 will be the same.
Open your PDF there, choose "Add page numbers", pick a pattern such as {NUM} and set "Min. digits" to 4. Page 1 then gets 0001, page 11 gets 0011 and so on. Save the PDF when you are done.