The exact number is 2097152 GH = 2 PH.
There is no exact number, just estimates.
I am saying that 2 PH equals to exactly 2097152 GH, for those interested to capture exact moment.
It does not.
2 PH = 2000 TH = 2000000 GH = 2000000000 MH = etc... You get the idea.
Lets not propagate the sillyness of the computer-storage world where standard metric quantities are mutilated to the nearest power of 2. It's all neat powers of 10 in the SI unit system, like it's supposed to be.