Does not mean it is real but a look up on the serial number returns 1883-O with variety "Rainbow toned". And I used that long number you posted.
Oh. When I tried typing it in, it said it wasn't in the database. I must have missed one of the 0s. Thanks mark.
Don't worry. That is the first time I remember seeing a number that long also. I guess I typically do not look at the yellow holder ANACs coins very much.