3554 Amun is an M-type Aten asteroid (meaning it crosses Earth's orbit) and a Venus-crosser. It was discovered on 4 March 1986 by Carolyn and Eugene Shoemaker at Mount Palomar Observatory. Its estimated diameter is 2.5 kilometers, making it one of the smallest known M-type asteroids.
Amun was once considered metallic, based on its M-type spectrum. However, like the asteroids 22 Kalliope and 21 Lutetia, the radar albedo of the object is inconsistent with a metallic composition. In Mining the Sky, planetary scientist John S. Lewis calculated the value of 3554 Amun at $20 trillion dollars .
(6178) 1986 DA is another M-type near-Earth asteroid with lower inclination that is actually metallic.
Amun passes closest to Venus, and in 1964, 2034, and 2103 comes within 10 Gm of it.