Answer:
What number has all letters in alphabetical order when spelled out?
Flat as a leaf, round as a ring. Has two eyes, can't see a thing.
Halo of water, tongue of wood. Skin of stone, long I've stood. My fingers short reach to the sky. Inside my heart men live and die.
It is weightless, you can see it. If you put it in a barrel it will make it lighter?
In we go, out we go. All around and in a row. Always, always steady flow. When we'll stop, you'll never known. In we go, out we go.
Those with eyes bigger than their stomach will definitely leave the restaurant with one of them. It is named after a house pet as well.