twelve
Genesis 17:20
"As for Ishmael, I have heard you; behold, I will bless him, and will make him fruitful and will multiply him exceedingly. He shall become the father of twelve princes, and I will make him a great nation.
Genesis 17:23
Then Abraham took Ishmael his son, and all [the servants] who were born in his house and all who were bought with his money, every male among the men of Abraham's household, and circumcised the flesh of their foreskin in the very same day, as God had said to him.