Can 'proportional to' be replaced by 'dependent upon'?

no.

No because it isn't.

I know it's the square of distance which's inversely proportional, but it can be concluded that it indirectly depends on the distance. I'm not calculation the gravity, I'm just stating the inverse dependence of distance on the gravity.
Anyways, let's leave science.
I wanted to know if it's logically correct to say 'inversely dependent' rather than 'inversely proportional'.

Again, no.

Inversely dependent means you can affect a random ratio to the equation, which is not the case with inversely proportional, where the ratio is a fixed one.

Thanks again!

So if, as you suggest, inversely proportional has a stricter meaning than inversely dependent, then inversely dependent can be substituted for inversely proportional. However, inversely proportional cannot necessarily be substituted for inversely dependent.

Which, in the end, is the answer to the question, don't you find?

Actually, no. The question was equivalent to, "Can inversely dependent be substituted for inversely proportional?"

I'm not good at nitpicking, Mark..

Really? You consider proper application of your own statement to the question that was asked nitpicking? It changes the answer.

You sell yourself short. Your reply (with the red ribbon) is evidence of that. And I honestly mean that in a very positive way.

Thanks for correcting me & Timur
I've de-selected Timur's reply as the answer, by the way

It's okay, I still give you credit for explaining the difference