I found that scale values show in the map always not in integer, and even worse, when I try to type in 50000, it automatically change to some wierd value like 41246.2638. I didn't use cache and BaseLayerGroup in my map. How to fix this?
Actually I have my own arthophoto image plus my several hundred of vector layers, So I don't use google map or Bing map.
My current solution for scale is applying a factor to my pdf map. For example actally map scale is 251234.1234, then I apply the factor of 251234.1234/250000 when I create a pdf,so I can write 1:250000 on the pdf, pdf size is specially for Letter, Legal and Ledger 3 choices. If I can draw a scale bar on the pdf then I don't need care about the scale value and paper size.
Extending Gordon's answer: If your map has tiled layers, your scales will always snap to the nearest finite scale in your Map Definition. That's probably what that strange looking number is. It's probably one of those finite scales.