Adding decimal separators to a YouTube view count retrieved via API

I’m trying to retrieve a YouTube view count for a specific video on my WordPress site. I’m not a coder but I’ve managed to get it working using this code:

<div id="viewCount" style="display: inline-block;"></div>
 <script>
       let getviewCount = () => {
        fetch(`https://www.googleapis.com/youtube/v3/videos?part=statistics&id=Cemk32wKN_k&key=XXXXXXXXXXXXXXXXXXXXXXXXXXXXX`)
        .then(response => {
            return response.json()
        })
        .then(data => {
            console.log(data);
            viewCount.innerHTML = data["items"][0].statistics.viewCount;
        })      
    }
    getviewCount(); 
    </script>

The final touch I’d like to add is decimal separators so instead of the number looking like this:

13526897

It looks like this:

13,526,897

Based on some research here I think I need to use a function similar to this:

function numberWithCommas(x) {
    return x.toString().replace(/B(?=(d{3})+(?!d))/g, ",");
}

But I don’t know how to code, so combining these two ideas is beyond my ability right now.

If anyone wouldn’t mind showing me how to do it, I’d be extremely grateful!

Thanks