Printf problem with big numbers....

I need to work with big integers ( around 2.^64), and I know it is not
possible to have integer that big.
So I use "double" instead, and it is ok with calculations.
But when I want to print them on screen or in a file, there is a
problem...

For example, if I write this :

printf("result: %lf\n",1234567890987654321.012345678);

What I get on cmd is:

result: 1234567890987654400.000000


Can anybody tell me WHY ?

.