[ID 17.2.20] Import xlsx spreadsheet: formatted numbers are truncated
MacOS 10.15.7 (19H1824) French localization
InDesign 17.2.0.20 (17200)
Excel 16.58 (16.58.22021501)
When importing an Excel sheet as a table, every number is truncated before the first thousand separator (which is a space in French).
1 457 will be imported as 1
21 457 >> 21
(21 457) >> (21
-210 457 >> -210
621 457 >> 621
and so on…
After a lot of tests on several configurations and discussions on the Adobe forum, I can say that the issue will only occur on French macOS systems, starting with Catalina. No matters what version of InDesign is used (15.0 thru 17.2).

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Maik commented
16 850 is not a number in terms of Excel. Cannot work. In your XSLX the (16 850) is left-justified and considered as text by Excel.
Solution: Set it to text format before importing to Indesign where it's text anyway.