Rule reminder
Mica is a colloquial negative intensifier. With non: 'non è mica stupido' = 'he's not stupid at all / don't think he's stupid.' Without non (emphatic/colloquial inversion): 'mica facile' = 'not at all easy.' It often implies the speaker is correcting an assumption.
Ha detto che l'esame era facile, ma non era ___ facile!