Number does not copy paste correctly

I want to paste this number in to a cell 8123896347296355
When I paste it shows 8.1239E+15
If I paste 812389634729635`5`it copies that ok
The number is being copied from a Chinese website (AliExpress) and then pasted in to my spreadsheet.
I have tried different formats text.general etc but that doesn't sort the issue.

Any thoughts to correct this.

You can format your cell as text and when pasting your number in, right click the cell formatted as text and select under paste options - Match Destination Formatting.

Welcome to one of Excel's more serious limitations.

Numbers as numeric values are limited to 15 decimal digits. This is due to finite precision of 64-bit binary representation. The number you're copying would just be a string of characters, in this case, decimal numerals, in the website, and 16 digits suggests it's a credit card number. When you try to paste it into Excel, Excel sees only the decimal numerals and tries to handle it as a number, which means Excel strips off the 16th/rightmost digit, effectively storing 812389634729635*10.

If you set the Excel cell's number format to Text before pasting, Excel would accept the pasted value as text and leave it intact, but it would be text consisting of just decimal numerals.

There's no way to paste 16-digit or longer numbers into Excel as numbers due to Excel's finite digital precision. Pasting as Text is the only practical solution.

hrlngrv....thanks for the explanation, i will mark as solved.