Seven

The seven Narakas are

1. Athala, 
2. Vithala, 
3. Suthala, 
4. Paathaala, 
5. Mahaadhala, 
6. Rasaadhala, 
7. Dharaadhala.

Similarly, the seven heavens are

1. Bhuvas, 
2. Swas (governed by Indra), 
3. Tharus, 
4. Thaarus, 
5. Savithaa, 
6. Prapithaa, 
7. Maha (governed by Brahma.