Yes, with our platform you can set up a this type of campaign with two different options:
1) With the Referral Contest option, you can reward the top referrer(s) for a certain time period. In your case it can be the people who invited the highest number of friends to sign-up to download your app.
2) Sweepstakes. Here you define the number of entries people will receive for a certain actions (entering email, social post, like/follow/subscribe, sign up or download) and at the end of the period the winner(s) will be chosen randomly. More entries = more chances to win.