Daniel Gilbert says in Magic by Numbers "The sound a number makes can influence our decisions about it" and gives some evidence. The article is discussed in
Phonetic Marketing where the the author's name is given as Daniel Olbert. One of the comments links to this interesting article Sound Symbolism by John Ohala.
P.S. I am posting it here since a couple of comments in Language Log did not go through and I liked immensely Daniel Gilbert's book "Stumbling on Happiness"
P.P.S. It is changed now.