A billion is one of those big deal numbers that make headlines. It’s such a huge number that we really aren’t able to wrap our heads around it, and that gives it a mystique that makes headlines. And this week Apple sold its billionth iPhone — but does that make it the best-selling product of all time?

It all depends on what you mean by products.

See also: How Android ‘switchers,’ a cheap iPhone, and the expensive iPad Pro saved Apple

To some companies, shifting a billion is no big deal. McDonalds sold its billionth hamburger in 1963 (taking 23 years to break that barrier), its 50 billionth in 1984, and its 100 billionth in 1993.

That’s a lot of product, but they’re consumables.

The billionth PC was sold in 2002, and it took 25 years to hit that milestone. The billionth Android device was activated in September 2013 (about four and a half years following the launch of the operating system), and by 2014 the operating system had a billion active users per month.

But you can argue that PCs and Android devices aren’t a single product because that billion was made up of devices from countless hardware OEMs, and not a single maker.

Back in April 2015, Microsoft set itself the ambitious task of getting Windows 10 onto a billion devices “within two to three years,” but earlier this month admitted that despite aggressive marketing and offering the platform as a free upgrade to consumers, it was going to take longer than planned.

Apple itself is no stranger to hitting billions. Last November it shipped its billionth iOS device (a category that not only included the iPhone, but also iPads and iPod touch devices).

But when it comes to a consumer electronics brand, the iPhone is unique, not only in hitting a billion, but in doing so in a little over nine years.

To put the iPhone into a different perspective, compare it to the iPod. As wildly popular and ubiquitous as that product was, it took Apple 12 years to sell 400 million units, by which point sales had collapsed to only a few million a quarter.

What’s more impressive than iPhone hardware sales is the revenue that this device has pulled in for Apple, considering that the average selling price for the iPhone over that time has hovered around $620 per device.

Given that iPhone sales are now slowing down, it might take Apple a fair bit longer to hit the next billion.

See also: