GANANATH

Shiva is known as Gananath because he controls the comrades. Shiva is the only chief of comrades. He is the only reckonable and he is Ganesha.
Gana is one who is reckoned. Shiva is the only precious object among all the reckonable things. Shiva is known as Gana because he is the most valuable and one who is desired by all, that is called Nath. Shiva is Nath even if he himself is Gana also, so he is named as Gananath. In front of Yamraj ( God of death), Upamanyu has boldly declared the Nath-nature of Lord. The word Ganapati which is found in Vedas, that also points towards Lord Shankar. Therefore Arjuna has addressed Lord Shankar by the name ‘Ganesha’— Ganesham Jagatah Shambhu Loka karan karnam. In the spiritual science Shiva is called as Gananath because through the living spirit (jiva) he controls eight comrades namely Karmendriya (working sense-organs), Gyanendriya (knowledge acquiring sense-organs), Antah-karan (subtle body), Mahabhoota (five material elements), Prana (life air), Karma (action), Kama (desire) and Avidya (ignorance). Here is the explanation of Bhaskar Roy, quoting Gananath as Sankhyanath—

शशिकरगुणमुखसंख्यानां प्रमथतुषितमयमुख्यानाम्।
अधिपतिरसि शिव! कैलासे पुरि निवससि गणनाथस्त्वम्॥

Purport: O Shiva! You are the master of numeric viz. one, two, three and you are also the master of genies like Pramath, Tushit and Maya. You are called as Gananath as you are established at Kailashpuri by this name. According to Puranas, Shiva is called as Gananath because he controls his servants and followers. He is also called Gananath because he gives birth to Lord Ganesha.