Has a FIBA World Cup game ever ended 81-46?
Exactly once. On September 3, 2014, Argentina beat Senegal 81-46, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 81-46 in league history.
That makes 81-46 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 82-46 has happened never and 81-47 has happened never.