Generally, Nation States stats are canon unless otherwise stated.

Kaprein's military, in comparison to a real life military, would be strong enough to defeat a combination of NATO as well as Earth's other large militaries. I don't think it'd win a fight if it faced every military on Earth combined (if it got to land combat, and WMDs weren't involved). If the combat was kept to naval and air fighting, Kaprein would be able to win if it kept to the defensive.

Kaprein's economy is significantly larger and stronger than any economy on Earth.

For more detail, including why I haven’t given a list of exact numbers for Kaprein, see Kaprein's Information, Disclaimers, and Tips: (Work in Progress) factbook page.