The given equation of parabola is
x2 = –16y, which is of the form $x^24 = –4ay.
∴ 4a = 16 ⇒ a = 4
∴ Coordinates of focus are (0, –4)
Axis of parabola is x = 0
Equation of the directrix is y = 4 ⇒ y – 4 = 0
Length of latus rectum = 4 × 4 = 16.