Seven is a round number which marked a large quantity.

At an earlier period five represented a numerical magnitude, and hence the Anunnaki are at times regarded as a group of five.[220] The Anunnaki and Igigi appear for the first time in an historical text in the inscription of the Assyrian king Ramman-nirari I., who includes them in his appeal to the great gods.

He designates the Igigi as belonging to heaven, the Anunnaki as belonging to the earth.

The manner in which he uses the names shows conclusively that, at this early period, the two groups comprehended the entire domain over which spirits, and for that matter also the gods, exercised their power.

Indeed, it would appear that at one time the two names were used to include the gods as well as the spirits.