Unfortunately, you cannot turn off specific notifications. There is only the ON/OFF options regarding notifications.
Note: You may have 17 Notifications, but only 5 appear. To see all of your Notifications, you need to click on the link to "See all" notifications under the bell Notifications' icon and they will display. Further, by clicking on the "Mark All as Read" link under Notifications, you can mark them as read as you review them.