Datatables export Excel

Question

I'm exporting the datatables in csv. And when I open the file with excel, I've got problem with big numbers (around 20 digits). I also have problem with the special characters. I guess it's a formatting problem. But I don't know How to correct the problem.

The code in my Js file:

dom: 'Bfrtip',
    buttons: [
        {
            extend: 'csv',
            text: 'csv',
            fieldSeparator: ';' // with ';' we can export the file in csv and each column is in one column. Without ';' everything is in one column
        },
        'pdf',
        'print'
    ]

An image of the problem: 

Thanks for your help.