This number is a composite.

+ The smallest square which is the sum of distinct primes using all ten digits (900 = 503+241+89+67 = 509+283+61+47). [Capelle]

+ The sum of square of first 900 prime numbers yields another prime {13459558559}. Note that 900 is also a square number. [Bajpai]

(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