JSFiddle - React, Tailwind, and code Playground

JavaScript

function fnum(x) {
  if (x < 1000000000) {
    alert((x / 1000000).toFixed(2) + "M");
  } else if (x < 1000000000000) {
    alert((x / 1000000000).toFixed(2) + "B");
  } else
    alert("More");
}
fnum(136866516683);