There is no such thing as inherent capacitance of a object. Capacitance is a property between two conductors. Your question therefore makes no sense. Capacitance of a typical human to where?
In the case of touch screens, the sensors are measuring capacitance back to their own ground. How well a human touching a sensor couples back to that ground has a lot to do with the surrounding physical layout. Capacitive touch sensors typically work on sensing a change of a few pF, sometimes even less than 1 pF, over a few 10s of ms.
In reading this over I think I left the wrong impression on how capacitive touch sensors really work. Actually, they only measure the change in capacitance as a conductive object such as your finger is put in close proximity to the sensor. Such a sensor has two plates, sometimes interleaved, so that putting your finger close increases the capacitance between the plates.
This doesn't change the fact that the human body will have some capacitance to the local ground, which is more what this question is about. Again though, there is no fixed inherent capacitance of a human body by itself.