Not even close.
The conquistadors of Mexico and Peru were outnumbered to a much greater extent than JC ever was.
Admittedly, their conquests were facilitated greatly by native rivalries, epidemic disease and resultant social collapse. But we're still talking utterly ridiculous disproportions in manpower.
The British conquered India with forces much less than a ratio of 700,000 to 300M.
Good thing Americans are all on the same page...