Kylie and BFF Jordyn Woods were in Calabasas when the photog snapped these pics. We're told they were headed to a meeting in L.A.

It looks like she has a flat stomach. True ... she's wearing black and has a fanny pack around her waist, but still ... bouncing back this way after less than 2 weeks seems almost superhuman.

Little Stormi was nowhere to be seen in the pics.

TMZ broke the story of Kylie's pregnancy back in September, and she all but disappeared from sight during her pregnancy ... a pregnancy she didn't publicly acknowledge until after the baby was born.

Hey ... good genes -- good for her.