Apple Inc. (NASDAQ:AAPL) has produced seven generations of the iPhone, but the iPhone 6 may surpass them all in sales.

Respected Apple analyst Amit Daryanani of RBC Capital Markets says Apple is preparing for demand in the 75 million to 80 million range for iPhone 6 and 6L devices in the December quarter alone, Apple Insider reported. If that pans out, it would outpace every other iPhone in history, not to mention a great many other Apple products.

Daryanani isn't actually predicting Apple will sell that many phones. His prediction is 65 million, including 10 million in the first weekend of launch, according to Business Insider.

But even on the low end, this will be the biggest iPhone launch ever, dwarfing the launch of the iPhone 5s and 5c, which saw 9 million sold in the first weekend and 47.8 million units sold through December 2013. On the high end of Daryanani's estimate, the iPhone 6 would nearly double the 37 million iPhone 4s units Apple sold in the same period of 2011. Apple's first iPhone, unveiled in August 2007, sold just 6 million units in its first year.

One significant difference is that Apple is selling the iPhone simultaneously in global markets.

One concern that emerged during the iPhone 5's cycle was waning interest and decreased orders the following year. But Morgan Stanley Securities analyst Katy Huberty proposes that Apple isn’t headed for such a fate this year thanks to several factors, including Apple’s online services, recent acquisitions and upcoming devices such as the highly rumored iWatch.

The demand for larger-screen iPhones is also expected to fuel sales of Apple’s rumored smartphone, which may be released as two models -- the 4.7-inch iPhone 6 and the 5.5-inch iPhone 6L.

The new smartphone is expected to have a number of new features, including a larger battery, improved camera and a highly coveted sapphire screen.

Apple is expected to unveil the iPhone 6 and the 6L during a media event on Sept. 9, with pricing likely to start at $199 and $299 with a two-year contract, while off-contract prices may fall anywhere between $600 and $700, according to analysts.