It's safe to download the app. Миронов Борис developed Мнемоника that falls into the Educational category. According to the latest info, the tool is rated 3.6 on Google Play.
This application has been downloaded and set up by over 100 users and its latest update is dated Dec 21, 2013. It's free to get the installer of Мнемоника, also, you can read users' reviews on Droid Informer. The app works fine on Android 3.0 and above.