You've arrived at the same order as my estimate of the real number of cases in Italy (I arrived at ~80k, see sibling comment), using a different technique. Your

You've arrived at the same order as my estimate of the real number of cases in Italy (I arrived at ~80k, see sibling comment), using a different technique. Yours seems more reasonable. But note that South Korea must inevitably have missed some cases, so assuming the same ratio of diagnosed to serious cases between Italy and SK. So the real number of diseased people in Italy must actually be a little higher.