How to divide really big numbers in Google Sheets

As part of the creation of an IBAN number generator, I need to divide a 26-digit number by the number 97 to find out the check digits in the IBAN number.
After about an hour of searching, I found out that Google Sheets cannot calculate with such large numbers - Google Sheets not processing very large numbers
But how to do it?
How to bypass this limitation in Google Sheets?
I am trying to find the first 6 digits after the decimal point after dividing a 26 digit number by 97.

I have the same problem in LibreOffice Calc.


I am not looking for a way to verify the validity of the entire IBAN number.
I am looking for a way to create check digits when generating an IBAN.