p can apparently be taken as about 1.6. Armed with this, we can plug some figures in. The average brain is apparently about 167 mm long, 140 mm wide and 93 mm high.
And how much surface area does the brain actually manage to achieve?
Around 2 m2, or 2 000 000 mm2. In other words, crazy as the sulci and gyri may look, the surface area is thereby increased by a factor of almost 10 times!
Told you I was a nerd.