The number of neutrons in the human body can vary depending on factors such as individual body composition and isotopic abundance. However, on average, an adult human body contains approximately 7 × 10^27 (7 followed by 27 zeros) neutrons. This estimate is based on the assumption that the average human body contains around 7 × 10^27 atoms, with roughly half of them being hydrogen atoms, which have no neutrons, and the rest consisting of other elements with varying numbers of neutrons per atom.