This number is a prime.

+ The product of the first n digits of 123479 (read left-to-right) is either one less or one more than a prime.

+ The smallest prime formed from all of the positive digits that are expressible as sum of two triangular numbers in exactly one way. [Honaker]

(There is one curio for this number that has not yet been approved by an editor.)

Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell