PDFTK Builder  and PDFsam  are the only free portable apps able to split or merge more than 140 pages.
If you need a free portable app able to split or merge 147 pages, you can use PDFTK Builder , which is available only in english, however. PDFsam is also portable and availaible in many languages (german also). 7-PDF Split & Merge  (german + english) can split only max. 50 pages and merge max. 5 files for free. If you want to to split or merge more than 50 pages you must pay 10 EUR for "7-PDF Split & Merge PRO".
 PDFTK Builder
 7-PDF Split & Merge