How does Excel autofilter chooses "Text filter" or "Number filter" and how can that be changed?

Question

While having a look at this other question, I realised there's another issue at hand here, as you can see from the following example:

Col1          Col2  Col3
9000113782BI     1     a
9000113782BI     2     b
9000113782KA     3    cc
9000113782KA     4     d
9000110011       5  
9000125379
53844653
588446563
25455875546

When I enable the autofilter, it chooses by default a number filter for "Col2", and a text filter for "Col3".
However "Col1" contains a combination of numbers and text, and the first entry clearly is text. Hereby a screenshot for clarification purposes:

Why does Excel chooses default for a "Number filter" in that case and how can that be changed?

Thanks in advance