Adding yet another positive note to Instagram’s biggest week ever — Facebook on Monday announced that it will acquire Instagram for $1 billion — the company’s new Android application has been downloaded more than 5 million times after less than one week of availability. Instagram launched for Android-powered devices on April 3rd, and it took less than one day for the highly anticipated app to reach the one million download mark. As of Monday, April 9th, the application had been downloaded from the Google Play marketplace more than 5 million times, The Next Web reported. Instagram allows users to capture photos or import them from a smartphone’s camera roll, and then apply retro effects before sharing them with their contacts. Facebook expects its acquisition of Instagram to close later this year.