Numbers in Norse mythology

Numbers are significant in Norse mythology although not to the extent which they are in some traditions e.g. as in Jewish cabbalism[?].

Particularly significant numbers are three, eight and nine.

The number three is both an invocatory and magic number:

When Loki is bound with the entrails of his son, the entrails are wrapped thrice around the rock.
The jaws of the wolf Fenrir are bound three times round to hold him by Tyr

The number three occurs with great frequency in grouping individuals and artefacts:

There are three Norns.
Odin had two brothers, Vile and Ve; i.e. there were three siblings
Yggdrasil has three roots, and three is the square root of the number of worlds on Yggdrasil, nine.
In the Gylfaginning in the Younger Edda, King Gylfi[?] is confronted by a triple throne at the false home of the gods, one being seated and occupied atop another.
Loki has three malign progeny by the giantess Angeboda[?]: the wolf, Fenrir, the world-serpent, Jormungand and Hel.
Prior to Ragnarok there will be three hard winters without an intervening summer, the Fimbulwinter.

The number eight is highly potent and arguably the most magically potent of the numbers.

Odin's steed, Sleipnir, has eight legs.
Odin's ring Draupnir gives forth eight more similar rings every ninth night.
Loki garnered eight gifts from the dwarves as recompense to the Aesir for the theft of Sif's hair (in two blocks of three and finally two).
In the guise of Grimnir in the Grimnismal, Odin awaits the attention of King Geirroth for eight days before causing his death
In the Reginsmal[?], the curse of Andvari's ring is laid upon eight heroes who shall wear it.

The number nine is also a magically significant number:

When Odin sacrificed himself to himself, he hung upon the gallows for nine days and nine nights
There are nine worlds on Yggdrasil;
The guardian of the gate, Heimdall is said to have been the son of nine mothers.
In the Skirnismal Freyr is obliged to wait nine nights to consummate his union with Gerdur Gymisdottir.
In the Svipdagsmal[?], the witch Groa grants nine charms to her son Svipdag[?].
In Fjolsvinnsmal[?] Laegarn's chest is fastened up with nine locks.