In the book "The Martian", how long was Mark Watney trapped on Mars (in Sols)?

In the book "The Martian" by Andy Weir, Mark Watney was trapped on Mars for 549 sols. A sol is the Martian equivalent of a day, and it is 24 hours, 39 minutes, and 35.244 seconds long. Mark was left stranded on the planet after his crew mistakenly presumed him dead during an intense dust storm and had to abort their mission and return to Earth. Mark, being a resourceful and determined astronaut, managed to survive by utilizing his scientific knowledge, engineering skills, and limited supplies to grow food, produce water, and communicate with NASA. His ordeal and efforts to stay alive stretched over a period of 549 Martian days until he was eventually rescued.