Комментарий к Берешит 41:49

עד כי חדל לספר UNTIL THEY CEASED NUMBERING — until the one who was numbering stopped numbering — it is an elliptical phrase

אין מספר; the amount was so great that there was no known word to describe such a number, such an amount in terms of grain.

עד כי חדל לספור, until he stopped counting. They stopped counting the accumulated amount of agricultural surplus because the people delivering the surplus for storage had not bothered to count it. Even though the Torah speaks about one fifth of the harvest being taxed, the farmers merely divided the harvest into five approximately equal piles, and delivered one pile to Joseph's silos. They did not bother to count the total amount they had harvested, however. Joseph's officials did not count, not having been told the amount the farmers claimed to have delivered.