Diameter: 142,984 km
Albedo 0.52
Perihelion distance from the Sun: 4.95042906
Visual magnitude: -2.5 at perihelion
You can change the reference numbers to any known object. You should get very similar results.
It also computes how fast an object appears to move against the background stars when viewed from Earth at opposition. Enter the diameter of the object, its albedo, its distance from the Sun, and its semi-major axis (same as distance for circular orbits). It will compute its visual magnitude as seen from Earth, as well as its speed against the background stars in arcseconds per hour.
Although the formulas use the MKS system of units, you can use any of the units in the dropdown lists and it will perform the unit conversion for you. This is written in Javascript. You can see the source code by choosing View > View Source from your browser menu.