0.387 A.U. or about 36 million miles. Note however that the orbit is quite eccentric, and so its distance from the Sun varies quite a lot. 88 Earth days, or 0.24 Earth years. Note that this makes the Mercurian year shorter than the Mercurian day.
Surface is no longer active.
Always observed close to the Sun. This is a consequence of its orbit being smaller that that of the Earth Once thought to rotate such that it always shows one side of the planet to the Sun. Now we know that it has different rotation and orbital periods. Surface shows scarp features, indicating that a solid surface has shrunk as the interior of the planet cooled. Largest feature is the Caloris Basin, formed by the imapct of a large asteroid.