1. The property bought by your father is the self acquired property of his and upon his death, your mother (if alive), you, your two brothers and your sister are entitled to equal share in the property, since your father has died intestate (without executing a WILL). If your mother is alive, then each one of you is entitled to 1/5th share in your father's self acquired property. In case your mother is not alive, then each sibling is entitled to 1/4th share.
2. To qualfy a property as an ancestral property, the property should have traversed for 4 generations without any division or partition during its traverse from great grand father to great grand son/daughter.
3. Based on the above explanation to ancestral property, you can arrive at a decision whether properties left behind by your father belongs to ancestral or self acquired properties or both. To answer your particular property reference as ancestral property, more details from you are needed.
4. If the properties were to be your father's self acquired property and since he has died intestate, all the legal heirs are entitled for equal share and the property cannot be sold without your consent.
5. To get your rightful share file suit for partition.