PDFill

PDFTK Builder is the only free portable app 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 [1], which is available only in english, however. 7-PDF Split & Merge [2] (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".
[1] http://alternativeto.net/software/pdftk-builder/
[2] http://alternativeto.net/software/7-pdf-split--amp--merge/

Tanks to nunomegas! I have changed the Title from PDFFill to PDFill.

Only with PDFill PDF Tools you can Split very big pdf-files with more than 200 pages for free:
The separating of the first 39 German-speaking pages from a TV operating instruction with 235 pages worked neither with "Adolix Split & Merge PDF" (max. 50 sides are possible) nor with "PDF Split and Merge 1.1.4". PDFill PDF Tools is the only excellent free pdf tool with which the Spliten of this so big pdf file functioned perfectly:
PDFill PDF Tools are FREE PDF Toolbox to Merge, Split, Reorder, Encrypt, Decrypt, Rotate, Crop, Reformat, Header, Footer, Watermark, Images to PDF, PDF to Images, Form Fields Delete/Flatten/List, PostScript to PDF, PDF Information, Scan to PDF, and Create Transparent Image.
Details see http://www.pdfill.com/pdf_tools_free.html

The alignment (rotation) of single pdf pages around a small corner (e.g., 2 °) is not possible with PDFFill (only 90 °, 180 °, 270 °).
With IRFANVIEW one can turn single pdf pages in a pdf document also about only few degrees, see http://alternativeto.net/desktop/irfanview/.

PDFFill has clearly more functions than "Adolix Split & Merge PDF" (max. 50 sides are possible) or "PDF Split and Merge", but the User Interface of PDFFill is only available in english language. Until now there is no multilanguage support.