You are right about it going over Everest though - The calculation obviously assumes a planet is a smooth ball. Once it becomes fractal it's quite different. it's also the same value of 6.28m for any size object, as it's to do with the change in radius, not the size of the object - which is certainly counter intuitive, I think.
Anyway, it does show why removing one link of a few mm's has such an effect on the tightness or looseness of a bracelet. A 10mm link makes nearly 2mm difference all the way round the wrist.