How to save a 15 digit # in CSV without it changing to a formula?

[Ab]

I have to save my excel sheet as a CSV, but the numbers I am using are 15
digits long and need to be kept that way. Every time I re-open the document
15 digit numbers are all changed to formulas, no matter how I format the
cell. Is there a way to do what I want or is that not compatable with CSV
format.

 

[David Biddulph]

What version of Excel?
What number is it changing to what formula?

Firstly check what is saved in the CSV. Open the CSV in something like
Notepad. In the CSV I would expect the number to be saved as you were
displaying it in Excel. Remember that a CSV is text. Usually any problems
are not in saving to CSV, but because someone then decides to open the CSV
with Excel, and uses Excel's default choices.

If you then open the CSV with Excel, then Excel will usually make its own
choice of format for displaying the number, but if it is an integer you can
format as number with zero decimal places. If you particularly want Excel
to import the number as text, you can do this with Data/ Import External
Data.