King Solomon [1 Kings 11 (4)] “had seven hundred wives, princesses, and three hundred concubines;” How many children did he have? Three. The question is referred to at http://wiki.answers.com/Q/How_many_children_did_King_Solomon_have Do we have a different/better answer?
R. Chaim Dov Rabinowitz (Daas Soferim) comments that it seems likely that Shlomo had 100 children or less (which would of course mean that most of his wives were childless), since in Eccles. 6:3 he speaks of that number as a peak of human potential.