19171...51719 (29-digits)

This number is a prime.

191715131 1975313579 1113151719

Single Curio View: (Seek other curios for this number)

The prime obtained by concatenation of the odd numbers 19 down to 1 and up to 19 again. [Gupta]

Submitted: 2025-08-19 15:08:52; Last Modified: 2025-10-01 01:07:44.