If you want a more precise answer, use 159155 instead of 159000. This is kind of academic anyway because of the tolerance of typical caps.
Where does this number come from? It's a kind of shorthand. The formula for capacitive reactance is
Xc = 1 / 2pi(FC)
Where Xc is capacitive reactance in Ohms, F is frequency in Hertz, and C is capacitance in Farads.
The reciprocal of 2pi is 0.159154943
Since it's generally inconvenient to deal in Farads, we can multiply 1/(2pi) by one million and arrange the formula like this
Xc(Ohms) = 159154.943 / Hertz * microfarads