This is an extension of this question about What limits chromosomal length?.
I am wondering what could be the specific reasons behind the number of chromosomes an organism carries. In other words, what drives the number of chromosomes and is there anything "stabilizing" the number of chromosomes.
Of course I am not talking about multiple copies of the same chromosome, i.e. trisomy, but rather the reasons behind the partition of the genetic information into a defined number of chromosomes.
From the question I referred to, chromosomes have an upper length limit which is based on their physical size, i.e basically they must be shorter than half of the spindle arm axis and they probably also have a lower limit. Yet it is unclear to me if any non-random equilibrium exists between chromosome number and length other than just being bound by an upper and lower limit in size.
Also let's restrict this question to diploid organisms to avoid organisms such as the Oxytricha trifallax which has 16,000 chromosomes but is also ampliploid or plants such as wheat which can be tetraploid.
I tried to search in the literature and couldn't find a satisfying answer. Also I had in mind the example of the Hela cells which have completely shuffled chromosomes yet still exactly 46.