The actuarial value of a human life is $10M, so that really is how the math works out. Don't underestimate the lifetime output of a human, plus all the non-monetarily-compensated labor they do that is nevertheless valuable. Especially if there are dependents involved (younger or older), the costs of that death rise well above just that person's economic output, but also the total cost of the state having to take on the burden of caring for those dependents. And we haven't even started getting into what the emotional burden on everyone who knew those people looks like.

The numbers work out; it's absolutely worth shutting down the economy for some number of months to prevent the loss of a million lives. Obviously the numbers don't work out to do so indefinitely, but for the one month so far and the upcoming few, definitely.