Apple said Monday that it has sold more than 4 million iPhone 4S smartphones since its launch three days ago, setting a sales record for the device.

Over the weekend, the company sold more than twice the 1.7 million iPhone 4s that it sold during last year’s opening weekend, though the numbers are a bit skewed: This year’s iPhone was simultaneously launched in the United States, Australia, Canada, France, Germany, Japan and the United Kingdom, while last year’s launch did not include Australia and Canada.

Also in the United States, the iPhone launched on multiple carriers for the first time. The iPhone 4S is also the first iPhone to be available on the Sprint network. Verizon previously sold the iPhone 4, but the device launched exclusively on AT&T.

Apple’s management said it was pleased with the results.

“IPhone 4S is off to a great start,” Philip Schiller, Apple’s head of marketing, said in a prepared statement. “IPhone 4S is a hit with customers around the world, and together with iOS 5 and iCloud, is the best iPhone ever.”

Apple also announced that more than 25 million customers have downloaded or purchased a device with iOS 5, the new mobile software that powers the iPhone, iPad, and iPod Touch. The latest version of the operating system became available on Oct. 12.

There were a few reported hiccups with the download last Wednesday, as Apple’s servers were overwhelmed with demand. The new iOS 5 operating system also crashed at least one popular app, Google Voice. The search giant’s phone application was pulled from the iTunes App Store this weekend after repeated reports of crashes. Google said it has a fix in the works and plans an update soon.

The sales record comes despite a more muted turnout at Apple’s flagship store on launch day Friday, with around 250 people waiting 90 minutes before the iPhone went on sale. Some speculated that the rainy weather in New York City was to blame.

The new iPhone appears physically the same as the iPhone 4, but the guts are improved: it features a new, faster processor called the A5, which debuted in the iPad 2. It also includes a better, 8-megapixel camera, an improved antenna, and Siri, the new voice command software that’s billed as an on-board personal assistant.

Siri has already become a cult sensation, inspiring glowing reviews and blogs devoted to chronicling her more amusing quotes. She’s got opinions about the meaning of life (“42”) and the best place to hide a body (“metal foundries” and “swamps” make the list).