According to new data from Samsung, the South Korean company has now shipped over five million units of their Galaxy Note II smartphone. The phone, which at 5.5″ is somewhere between a phone and a tablet, includes a unique ‘S Pen’ stylus and multi-tasking features which set it apart from other phones on the market.

Samsung had previously announced that the phone, which was released in September this year, had sold 3 million units as of the start of November. That means that the phone has sold a further 2 million units in November alone, making for an impressive overall sales record. By contrast, the original Note sold 12 million units in its first year of sales and the comparably sized LG Optimus Vu sold only 500,000 units between March and August.

These so called ‘phablets’ may not be popular for long, however. The Galaxy S series has grown with each generation – the original Galaxy S had a 4″ screen, the Galaxy S II moved to 4.3″, the Galaxy S III to 4.8″ and the next edition, the Galaxy S IV, is expected to have a full 5″ display. While the case for the Galaxy Note II will perhaps remain a strong one until the release of the Galaxy S4, with flagship phones continuing to grow a future Note device will need to get correspondingly larger or continue to differentiate itself with stylus-specific features.

It’s not just Samsung’s phones that are getting larger either. The famously small iPhone finally made the jump to a 4″ diagonal with the release of the iPhone 5, while on the Android side of things a 5″ 1080p display is quickly becoming the norm for 2013. Phones like the HTC Droid DNA have already been released with the form factor, and it seems every major mobile manufacturer is planning to follow suit.

All of this leaves the Galaxy Note II in an uncomfortable place. While many people are accepting that a large display makes a lot of sense that is primarily touch-based, the 5.5″ display is only a resolution of 1280 x 720, putting it firmly in last year’s smartphone generation. Samsung will no doubt be looking to follow up their continuing success with a Note III, but it’s hard to see what shape that will take.