12210 as a tree of primes

What does P.FACT do? 12210 is divided by the smallest prime that fits: by 2, then by 3, then by 5, then by 11, and 37 is left, a prime. So $\displaystyle 12210 = 2 \times 3 \times 5 \times 11 \times 37$.

▶ Watch this step in the video (1:10:47)