Regarding the episode is about tanks then yes. Poland was fifth army in the world.
- USSR 6000 tanks (number reported in various reports) (at the end of 1939, so after invasion on Poland, it was reported USSR have 11k light tanks)
- Germany 2800
- France 2600
- Great Britain 1150
It was fifth regarding tanks and planes but as you can see from above link the gap is quite large.
The number for Polish number of soldiers is AFTER mobilisation. Which is quite smaller than expected (around 1,35 million) due to lack of weaponry to equip soldiers. While at the same time Germany number is actual people serving in the army.