Frontend Interview Question: How to use CSS to surround a circle around a number

I recently came across an interview question where it involves creating a circle around a number. And the number needs to be in the center/middle of the circle. Without downloading a png file to have the number overlap, below is a solution where it requires a change to the CSS of the div.

This is what the end product should look like.

CSS file

.numberCircle {
    border-radius: 50%;
    width: 36px;
    height: 36px;
    padding: 8px;

    background: #fff;
    border: 2px solid #666;
    color: #666;
    text-align: center;

    font: 32px Arial, sans-serif;
}

Javascript file

<div class="numberCircle">30</div>