Here the order matters (the medal of the 1st is different from the medal of the 2nd, etc.) So it's a permutation (arrangement) of 6 chosen among 31:
³²P₆ = (n!)/(n-r)! = 32!/26! = 652,458,240
Another method: the 1st medal could be won by 32 the 2nd medal could be won by 31 . the 3dd medal could be won by 30 .etc. etc. the 6th medal could be won by 27 . Then the number of possibilities = 32x31x30x29x28x27 =652,458,240