iPhone 4S sold four million devices in the first three days since it debuted on Oct. 14 in part because Steve Jobs died only one day after it was unveiled (Oct. 4). Coupled with the fact Siri voice recognition comes with the it, it's actually kind of surprising iPhone 4S didn't sell more. Not that the whole process has gone smoothly for Apple, but those huge sales totals tend to even out things like slow iOS 5 downloads.

Of course, losing Steve Jobs couldn't have been forseen, and it must have been hard for many Apple workers to know he wouldn't be around to see his new invention shattering sales records. But, his death may have done more to stimulate iPhone 4S sales than any other single factor. Here are the top five reasons Apple was so successful with the newest iPhone.

Steve Jobs' Death

Apple has lost its creative genius and he died only one day after iPhone 4S was unveiled. Other devices will come out that Jobs had a hand in developing, but iPhone 4S will always have a special association with its creator. That's why many will probably buy an iPhone as a memento to remember the charismatic tech titan by. As long as people have iPhones, they will be a keepsake they can forever associate with Jobs.

iOS 5

iOS is now available for iPod Touch, iPad, iPad 2, iPhone 3GS, iPhone 4, and iPhone 4S and is a leading reason people have gravitated toward Apple products. iOS 5 has over 200 new features and streamlines the interface to make it more user friendly. Twitter is integrated so you can tweet from anywhere and all notifications are now kept in one place.

Siri Voice Recognition

Siri was the most highly praised feature of the iPhone 4S launch. Just ask Siri, 'what's the weather today,' and it will find out and speak an answer to you. It also can create text and email messages just by hearing you say it.

Sprint Now Has iPhone

This item could arguably be higher because Sprint is the third largest carrier in the U.S. For $199, Sprint subscribers can purchase the iPhone 4S and for just $99, an iPhone 4. That's thousands of thousands of people who didn't want to break their Sprint contract to go to AT&T for their mobile devices. Ironically, the deal might not be all that great for Sprint because the reportedly paid for millions of devices ahead of the lauch before they enen knew how many would sell. On the other hand, the record breaking sales numbers could pay off for Sprint in an unprecedented way.

World Phone

CDMA and GMA allows business travellers to use the phone on two continents. It's an important step because Apple knows how many businesspeople predominantly use BlackBerry. Apple can tap into that segment of users starting with the world phone capability.

Tell us in the comments if you think iPhone 4S wil be the greatest selling tech gadget of all time.