perl -lne '$d=pack("d",$_);$b=unpack("b*",$d);printf("%s (%d bits)\n",$b,length($b))'
518819.748032
1000001110011000001111111011111101110001010101011111100010000010 (64 bits)
64852.468503656
0100100010000110110111111011111101110001010101011111011100000010 (64 bits)
^C