You could've made some little effort to visit the ISB website and check out their GMAT range.
Here is the link: http://www.isb.edu/pgp/visit/Brochure_2006.pdf
The GMAT range is 600 to 780 with an average of 706. So we're looking at a score above 700 in general to get a good chance. More than 65% of those admitted score higher than 700. only 5% score between 600 and 640.
And YES, ISB requires recommendations.