Have to go to class, haven't got time to post longer, but two quick comments:
Quote:
Originally Posted by Mithadan
There are only two exceptions to the litany of odd and prime numbers that are of any real mythological significance in Tolkien's work, at least that I can think of. The 2 Trees and the 2 Lamps of the Valar. Again, any significance here?

Well technically 2 is also a prime number, but since its even it doesn't tend to be viewedthe same way, and has a different feel or effect in mythology / literature. It gives a feeling of a pairing (dark/light, sun/moon, etc).
And in general, I think that certain numbers may be chosen because they are "visually appealing". Not in their written form sense, but in the quantity. Even numbers have symmetry. Odd numbers are unpaired. Compare a Magen David to a pentagram  they have a different "feel" based on the visual pairing or symmetry of rays/angles. I think it's the same here. Odd  and especially prime  numbers stand out because they aren't easily grouped (and 9 is grouped in a 3 of 3s, which is also prime and asymmetrical).
Great thread, sorry I can't post more, but I gotta run now.