Passage: The potto grows to a length of 30 to 39 cm, with a short (3 to 10 cm) tail, and its weight varies from 600 to 1,600 grams (21 to 56 oz). The close, woolly fur is grey-brown. The index finger is vestigial, although it has opposable thumbs with which it grasps branches firmly. Like other strepsirrhines the potto has a moist nose, toothcomb, and a toilet claw on the second toe of the hind legs. In the hands and feet, fingers three and four are connected to each other by a slight skin fold, while toes three through five are joined at their bases by a skin web that extends to near the proximal third of the toes.The neck has four to six low tubercles or growths that cover its elongated vertebrae which have sharp points and nearly pierce the skin; these are used as defensive weapons. Both males and females have large scent glands under the tail (in females, the swelling created by the glands is known as a pseudo-scrotum), which they use to mark their territories and to reinforce pair bonds. The potto has a distinct odor that some observers have likened to curry.

Question: How many ounces is equal to 600 grams?
21