If textgcd(a,b)=64\\text{gcd}(a,b)=64textgcd(a,b)=64 and textlcm(a,b)=640\\text{lcm}(a,b)=640textlcm(a,b)=640, what is atimesba \\times batimesb?
640640640
704704704
409604096040960
409640964096