Google "multiple feedback low-pass filter".
At these component values corner feqs sit at 553.925 Hz and 510.926 Hz. The slope is 60 dB/decade (3rd order). Phase response corresponds normally to the slope, lagging ~135 degrees at corner.
The corresponding poles are at
-553.925 +j0 Hz and
-248.225 +/-j446.575 Hz
which gives a damping ratio of 0.485