Decimal to hex string
<p>I have a decimal value of a utf-32 character:</p>

<pre><code>$a=21644;
</code></pre>

<p>How can I convert this using php to a <strong>string</strong> of the hex? <code>'548c'</code></p>

<p>Here is the page for the codes I am using:
<a href="http://www.fileformat.info/info/unicode/char/548c/index.htm" rel="nofollow">http://www.fileformat.info/info/unicode/char/548c/index.htm</a></p>
