To find your unique AdSense publisher ID number, sign in to your AdSense account at http://www.google.com/adsense. You'll see your publisher ID number displayed above the help search box in the top corner of your account.
Alternatively, you can find your publisher ID number within your AdSense code. Just locate the AdSense code in the HTML source code of your website, and you'll spot your publisher ID in a line like the one shown below:
google_ad_client="pub-xxxxxxxxxxxxxxxx";
