Trace private number on cell

we cannot trace that....... :)

We cannot trace that number as it is not visible to us. But mostly it comes because the network people need our documents if we wont produce them as many they asked
then numbers wont be visible and it will show private number

These numbers are not traceable by common man. Even if you try to call such numbers back, you will find no such number in you received call list.

To trace such numbers , you need to approach main network office or cops