Apple shipped its billionth iOS device in November

Of Apple's many record-breakers and milestones, here's a really big one: In its latest quarter, the company shipped its 1 billionth device running its iOS smartphone and tablet operating system.

"It was truly a momentous quarter for iOS," CEO Tim Cook said on a call with analysts Tuesday, after the company released its fiscal first-quarter earnings report. "On November 22, we shipped our 1 billionth iOS device. It was a space-gray 64-gigabyte iPhone 6 Plus, which we've saved here at Apple."

"One billion devices is an almost unfathomable milestone and we are all incredibly proud to be a part of it," he continued.

Among the many eye-popping numbers from Apple's record-setting holiday-quarter report, Cook said the company on average sold more than 34,000 iPhone smartphones "every hour, 24 hours a day, every day of the quarter."

He added that the company had over half a billion customer visits at both physical and online stores during the quarter and that the new iPhone 6 was sold in 130 countries by the end of the period.

The iPhone -- first introduced in 2007 -- is Apple's most important device and its biggest moneymaker, accounting for more than half of sales and about 70 percent of profit, according to analysts. For its fiscal first-quarter results, the Cupertino, Calif., electronics giant said it sold a record 74.5 million iPhones during the period, up 46 percent from its record 51 million sold in the year-earlier period and easily beating analysts' estimates.

The major contributors to that huge increase are the new, bigger-screen iPhone 6 and iPhone 6 Plus, which went on sale in September. Cook said the smaller, 4.7-inch-display iPhone 6 was the most popular model.

Asked during the call if Apple could sustain such strong growth rates for the iPhone, Cook said his company is "very bullish" on the device's future prospects. He said the iPhone 6 brought in the most new customers to the iPhone in the latest quarter than any prior launch and the most switches from Google's rival Android mobile operating system compared with the last three launches (the company didn't check later years).

Cook added that the install base of iPhone 6 is "barely in the teens," as a percentage of total iPhones in the market. A combination of people who haven't yet upgraded their iPhones, new smartphone users and potential Android switchers provided three large growth areas for the phone, he said.