upside down
(another Prime Pages' Glossary entries)
The Prime Glossary
Glossary: Prime Pages: Top 5000:
GIMPS has discovered a new largest known prime number: 282589933-1 (24,862,048 digits)

"Turning a number upside down" refers to the process of inverting a number's decimal representation by rotating it 180o (see the counter-clockwise example below).

A Number Turned Upside Down

See Also: Strobogrammatic, Tetradic, TriadicPrime

Chris K. Caldwell © 1999-2020 (all rights reserved)