With this information, you can calculate the quantity of knots 644 miles per hour is equal to.

¿What is the inverse calculation between 1 knot and 644 miles per hour?

Performing the inverse calculation of the relationship between units, we obtain that 1 knot is 0.0017869246 times 644 miles per hour.

Which is the same to say that 644 miles per hour is 559.6207 knots.

Six hundred forty-four miles per hour equals to five hundred fifty-nine knots. *Approximation

A knot is zero times six hundred forty-four miles per hour. *Approximation