The Athavarshirsha Ganesha mantra is said to have been composed by Maharishi Athavarshirshaand this mantra text is nothing to do with the 108 Upanishads of Post-Vedic time. The Atharvashirsha Ganapathy Upanishad mantra can be recited by anyone who adheres to yama andniyama, irrespective of caste, creed, language and ethnic factors. Being a moola mantra, it will have its own effect even if one recites with faith or not, implying that it even transcends all religious barriers. Sacred heart is more important than wearing symbolic sacred thread with the mind filled with all sorts of impurity.
Reciting the Atharvashirsha regularly empowers a devotee tremendously. Different means of worship confer different benefits.