19. (6 points) Xiao Ming puts 127 Go stones into several bags. No matter how many stones a child wants (not exceeding 127 stones), Xiao Ming can satisfy the request by taking out a few bags. How many bags does Xiao Ming need to prepare at least?
【Analysis】Since $127=1+2+4+8+16+32+64$, and the sum of any 1, 2, 3, ... numbers from $1, 2, 4, 8, 16, 32, 64$ can form consecutive natural numbers not exceeding 127, the answer can be derived from this.
【Solution】Solution: Since, $127=1+2+4+8+16+32+64$,

Therefore, at least 7 bags need to be prepared,
Answer: Xiao Ming needs to prepare at least 7 bags;
So the answer is: 7.
【Comment】The key to solving this problem is to split 127 into the sum of several numbers, and the sum of any 1, 2, 3, ... numbers from these can form consecutive natural numbers not exceeding 127.