*especially for users of base-ten notation*

I saw the following number, allegedly prime, in the twitter stream of Cliff Pickover:

The number consists of 252 `9`

's, then a single digit `8`

, then 253 `9`

's'

This file is a Sage worksheet with a brief calculation to confirm the number's primality.

- Hal Snyder

[252, 1, 253]
506

99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999989999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999

True
CPU time: 18.91 s, Wall time: 20.28 s