639

This number is a composite.

+ The smallest number that can be expressed as the sum of the k first prime numbers for some k, and congruent with 3 modulus 4. [Rodrigo]

(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