This may have already been done but thought i'd post anyway in case.
43 points is the number that mathematically sees us safe due to Leeds significantly worse GD. Which is 2 wins, 2 draws for us. Neither Leeds or Burnley can get to 42 points either with the games left.
Meaning that the following points totals have the following implications for all teams involved. I am basing this on the other teams only getting the points mentioned below, not what they can mathematically get (e.g maximum points, already covered).
41 (2 wins out of our remaining 4 games)
Southampton: would have to get a draw against Liverpool H or Leicester A. However, it's unlikely they will finish with a better GD than us regardless.
Burnley: Would need to take 7 points from 9 against Spurs A, Villa A, Newcastle H. Burnley likely to finish with a better GD than us in my opinion
Leeds: Neither of the above 2 teams would matter to us because even if Leeds got 7 points from 9, they would have a worse GD than us.
EVERTON STAY UP ON GD AHEAD OF LEEDS (AND LIKELY SOUTHAMPTON TOO)
40 (1 win and 2 draws out of our remaining 4 games)
Southampton: If Southampton lose both games they finish on 40. Would almost certainly finish below us due to GD.
Burnley: Would need to win 2 out of their last 3. Burnley likely to finish with a better GD than us in my opinion
Leeds: Would need to win 2 out of their last 3. WIll finish below us on GD.
EVERTON STAY UP ON GD AHEAD OF LEEDS (AND LIKELY SOUTHAMPTON TOO)
I personally don't think 2 wins out of 3 can be written off for either Burnley or Leeds so I think 40 points is the total that will see us safe, even if not mathematically. It also keeps Southampton in the conversation for us.
But due to Leeds poor GD if we match their final points total as everyone knows, then they will go down regardless.