Although I am pretty sure your reponse was sarcastic, just in case it wasn't. Atheism is by definition the rejection of  theistic belief. Therefore it is not a religion in ANY way but the rejection thereof. It is itself nothing other than that, and has not belief or worhsip or doctrines. Which is why many atheists will usually contextualise their position and talk about what they DO believe in. But it is very specifically the opposition of religious belief.