In order to remove your app from the AppStore, please visit https://itunesconnect.apple.com , enter your information and click on the arrow to the right of the Password field.
click on the "My Apps" in the main menu
Select the application you want to delete and press it.
After that, go to "Pricing and Availability".
And remove the application from sale.
After performing these actions, go to the "Application Information" menu.
Now you can remove your application by clicking on the button shown in the image.