The capital of the Nivadakavachas, demons who lived in the depths of the ocean.
Indra asked Arjuna to kill them.
For this he received the conch Devadatta, which, when blown, caused fear in the enemy. Matali, Indra’s charioteer, drove Arjuna to the Nivatakavachas. Arjuna stormed Hiranyapura and killed them.