How Long Could a Human Survive on the Sun?

The question that came into Randall Munroe's What If? series (previously at Neatorama) specifically asked if a human could survive a nanosecond on the sun if he were teleported there and back instantly. That glosses over the danger of approaching and leaving the sun, because a human couldn't survive long enough to get near the surface if traveling in a conventional manner. But a nanosecond is a billionth of a second, and a millisecond is a thousandth of a second, so this question deserved to be explored. You'd want to know what to expect before you embark on such a mission, if it were at all possible. The surface of the sun is a few thousand degrees, which is pretty darn hot. The interior of the sun is much hotter, so your teleportation machine would have to calibrated just so. Just to be safe, if you want to teleport somewhere to warm yourself up, make it the Seychelles, and stay longer than a nanosecond.