It doesn't mean anything as a single word, as far as I know. It is a brandable name that can be broken down into "app riot".
The reasons it might be appealing are:
1) it is short and easy to pronounce (if you design your logo so that the app and riot are clearly separated).
2) it has the preffix app, a hot technology buzz word identifying it as a company involved in software / web app development.
3) the relevant meaning of riot here is "impressively large or varied display of something", which is a positive connotation. There is also the negative connotation of riot, which is why I would avoid it.
4) It is reminiscent of "apricot", which is kind of cute.
5) There seems to be an existing company using this name doing Android development.
6) Other unknown / subjective reasons.