You can try a Custom Number format. Tableau Quick Tip #2 Custom Number Formats - Clearly and Simply
I'm not sure what options to use off the top of my head, but I'd think you could display "5,000,000" as "5M" if you really wanted to.
Unfortunately, they want the entire number so displaying it as 5M wont work.
I'd need to see your TWBX to be able to suggest any other options. If they NEED to see the full value, your only options are to reduce size or increase the space allowed for your values. What type of solution were you expecting? I'm not sure how else you'd address the issue without trimming the values.
You had asked: Is there a way to have this display differently?
Changing the Units is my suggestion for displaying this differently, but I'm wondering what other types of solutions you were expecting here (perhaps you had something in mind already)?
The ###### comes when there is not enough space for the number.
Have you tried to make the column wider by dragging it toward right?
The screenshot below shows the line indicator, but mouse pointer is missing.
I just tested Tableau's limit for showing whole numbers.
I think it can show 999 trillions, and therefore also 100s of millions.
See more in screenshot below and attached packaged workbook.
You'll likely notice that when using measure names, all columns in the measure Values card are the same width. Should you want different widths, then change the enormous column to discrete and pull it out of Measure values onto the row shelf -- then you can modify that column's width separately.