The analogy that most closely represents the number of cells in an average-sized adult human is the number of grains of sand on a fairly large beach.
Humans are estimated to have approximately 37 trillion cells, which is an extremely large number, much like the countless grains of sand found on a beach. In contrast, the number of bees in a beehive, human beings in New York City, and planets in the solar system are considerably smaller in comparison.