who will be having more rights on my father's property?

Hello Sir, Good Evening. I am expecting answer for the below question. Kindly help me with this. I am Sindhu and currently staying in Hyderabad and married since 5 years. I have one elder sister who is also married. And dont have any brothers to me. My mother expired 2 years back and my father got married again after my mother's death at the age of 61 and dont have any childern for them again. My father have one property (house in an apartment) which was registered under my mother's name and is still on my MOTHER's name. So some people told me that me,my sister and my father have equal rights on that house. And even if we want to sell it then all of us has to put the signature. Is this correct? But few days before my father's 2nd marriage me and my sister put signatures on No Objection Certificate so that my father can sell it to whom he wants. We have some financial problems with my step mother so wanted to know who will be having more rights on my father's property.