It was built by Ptaclusp Associates at twice the normal size (of mixed granite and limestone blocks) with black marble facing with an electrum capstone and two of everything else. It was completed in three months, using a workforce of forty thousand workers (actually two thousand workers that had been time looped). The walls sloped in at a precise 56 degree angle.
Because of its size, it found it difficult to flare off and wound up interfering with the other pyramids. Eventually it levitated and moved the land of Djelibeybi ninety degrees off the Discworld's time/space-axis.
Teppic eventually enabled it to discharge, removing the time-pressure and enabling the un-rotating of Djelibeybi. Afterwards, it disintegrated, returning to its individual blocks.
Interestingly enough, in Shea and Wilson's Illuminatus! opus, the main city of Atlantis was built around a super-pyramid that levitated above its base under its own power. During the natural disaster that destroyed the continent, the pyramid crashed back to its base, but because of its advanced construction was otherwise undamaged and still there several thousand years later to act as the inspiration for the pyramid on the USA's one-dollar note.
No doubt the only pyramids left in Djelibeybi are those which adorn the currency....