An Apple customer displays his newly purchased iPhone 4s outside of the Apple Store on Broadway and 67th Street in New York City. Apple said that it had sold more than four million new iPhone 4s models in their first three days on the market.

Apple said Monday that it had sold more than four million new iPhone 4s models in their first three days on the market.

Sales took off as the greatly upgraded version of the was released to the market on Friday in seven countries: the United States, Australia, Canada, France, Germany, Japan, and Britain.

Apple said more than 25 million customers have adopted its brand new mobile operating system -- included in the 4s -- called iOS5, and that 20 million have signed up to use its iCloud cloud computing, or online data storage, system.

The 4S was launched on October 4, one day before visionary Apple co-founder and longtime died following a long battle with cancer. His health failing, Jobs had stepped down as chief executive in August and was replaced by , who presided over the launch of the new .

It will be available in 22 other countries, including much of Europe, by the end of October, and more than 70 countries by the end of 2011, Apple said.