I'm pretty sure an individual number doesn't exist at all independent of the material being viewed. Visible flickering is gone by 90Hz, beyond that the speed of objects determines how visible the framerate is. If your framerate is too low you get to make a tradeoff between strobing and persistence of vision motion blur artifacts. Strobing (think CRTs or VR headsets) is visible as duplicate images, persistence of vision motion blur makes the image blurred (typical LCD, although some gaming monitors support strobing). If the difference between individual duplicate images or the motion blur is small enough that you can't see it, there should be no issue. That difference or blur is a function of how far the object moves between frame updates, therefore its visibility should depend on the speed of the objects as well as the framerate.
If you need to consider time delay, say how far a finger on a touch screen is ahead of the image being displayed, that's a whole other can of worms.