Tech giant Apple sold 15.4 million iPads in the last quarter, even exceeding analysts' expectations of 13 million units, according to the company's fiscal report released Tuesday.

Apple even sold more iPads than Hewlett-Packard, the world's top PC maker, sold laptops, desktops and tablets combined (14.7 million units) in the same quarter.

Speaking at a conference call, Apple CEO Tim Cook said the numbers prove that cheaper tablets, including the Barnes & Noble Nook and the Amazon Kindle Fire, pose no threat to the iPad.

I think people really want to do multiple things with their tablets, Cook said. We don't really see these limited-function tablets and e-readers being in same category. In terms of competitiveness, the ecosystem for iPad is in a class by itself.

Not surprising, considering the Apple App Store boasts more than 170,000 applications designed specifically for the iPad, while the cheap tablets have just a few hundred.

Cook believes the iPad's powerful capabilities are the major reason for its success in the competitive tablet market. The low-cost tablets will sell a fair number of units, but I don't think that people that want an iPad will settle for limited function. We're just going to continue to innovate like crazy in this area. And we think we can continue to compete with anyone that is currently shipping tablets, or that might enter in the future.

And, to the Apple fans who are wondering if the popularity of iPad has impaired Mac sales during the last quarter, Cook said the 5.2 million Macs units sold speak otherwise. On the contrary, the iPad has eaten into the sales of low-cost laptops or netbooks from other hardware manufacturers, rather than Macs, according to Cook.

Moreover, Cook expressed confidence in the iPad in the future, calling it a huge opportunity for Apple over time. He continued: There will come a day when the tablet market in units is larger than the PC market. In fact it's interesting to note that in the U.S., it's clear from IDC's recent data on desktop PCs that tablets exceeded desktop PC sales last quarter. You can already see different indicators that there is significant momentum in this space.

Meanwhile, even as Apple is celebrating its record-breaking success, the rumors about the next generation iPad, dubbed iPad 3, are surfacing endlessly.

The recent rumors indicate iPad 3 will boast of a high-definition display, a quad-core processor, much-improved camera system, Siri and LTE 4G capabilities.

Can the iPad maintain its dominance in the future? Leave your comment below.