This number is a composite.

+ If you factor 129 into primes (3 * 43) and concatenate (343) you get a perfect prime cube (73). Note that 129 is the smallest sum of distinct seventh powers (17 + 27). [Brueggeman]

+ 129 is the sum of the first |1-2-9| primes. [Nilsson]

+ The smallest sum of the first n primes that is divisible by three (n=10). [Gaydos]

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

Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell