SQL Server Add a column that holds the same random number for every 48 records

Question

I want to add a random invoice number plus the current date for every 48 records. I am sorting by a column called Billing code. I want to insert the random number plus the current date into a column called "Invoice_Number".

Below is an example of what I am trying to do:

Example Random Invoice Number In the image example, notice how the "Invoice Number" changes after 48 records.

This is not the actual code that I am using but I just wanted to give you an idea on what I am trying to achieve. The column for ' ' AS INVOICE_NUMBER is where I would like the SQL statement to insert a random number plus the current date.

    SELECT
       RECORD_ID,
       NAME,
       BILLING_CODE,
       '' AS INVOICE_NUMBER
    FROM BILLING_TABLE
    ORDER BY BILLING_CODE DESC

I am using Microsoft SQL Server Management Studio 2016

Any help would be grateful.