Answer
Center at $\quad(0,0).$
Vertices at $\quad (-4,0),(4,0),(0,-4),(0,4)$
Focus at $\quad(0,0). $
Work Step by Step
Divide the equation with $16$ ... (we want the standard form)
$\displaystyle \frac{x^{2}}{16}+\frac{y^{2}}{16}=1$
$\displaystyle \frac{x^{2}}{4^{2}}+\frac{y^{2}}{4^{2}}=1 \quad $...$a=b=4,$ a circle, radius $=4$.
(both axes are main axes)
Center is at $(0,0)$.
The focus of the ellipse is at its center, $(0,0)$.
The vertices are $(-4,0),(4,0),(0,-4),(0,4)$