Orangutans are about 5 to 7 times stronger than the average human. Their strength is primarily in their arms, which are adapted for arboreal living—hanging and swinging from tree branches. Adult male orangutans can easily lift or pull objects weighing between 200 to 300 pounds, and some might be capable of lifting as much as 500 to 600 pounds. Their stronger muscles (especially deltoid, pectoral, and latissimus muscles) and mechanical leverage due to longer arm muscles and bone geometry give them this extraordinary strength. Additionally, their grip strength can reach about 600 pounds, which aids their ability to move through the trees safely and efficiently. Despite this immense power, orangutans have a gentle nature and seldom use their strength aggressively.
In summary, orangutans are significantly stronger than humans in terms of raw pulling and lifting power, especially suited for their life in the trees.