<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
    <script type="text/javascript">
        function encodeNumber(n) {
            const a = (n & 0xFFFF);
            const b = (n & 0xFFFF0000) >> 16;
            const c = (n & 0xFFFF00000000) >> 32;
            const d = (n & 0xFFFF000000000000) >> 48;
            return String.fromCharCode(a, b, c, d);
        }

        function printN(n) {
            //document.write(`<p>fn(${n}) = ${encodeNumber(n)}</p>`);
            console.log(n, encodeNumber(n));
        }

        printN(0);
        printN(9);
        printN(1000);
        printN(Number.MAX_SAFE_INTEGER);


    </script>
</body>
</html>