This is happening because Excel sees these cells as numbers, but because they are so long they are being interpreted as Floating Point numbers. Number formatting precision in Excel maxes out at 15 digits as explained here.
What you should probably do is handle each value as a string
. Adding a single '
at the beginning of every cell with data in it should fix this issue up, or you can format all the cells as a string
or text
.
This method is not without it's limitations, however. If you are going to be processing this data then you may need to have some way to sanitize the data before feeding it into whatever processes it.