#666 New International Version
This calls for wisdom. Let the person who has insight calculate the number of the beast, for it is the number of a man. That number is 666.
New Living Translation
Wisdom is needed here. Let the one with understanding solve the meaning of the number of the beast, for it is the number of a man. His number is 666.

English Standard Version
This calls for wisdom: let the one who has understanding calculate the number of the beast, for it is the number of a man, and his number is 666.#666