521
This number is a prime.
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521 is the sum of two squares (112 + 202).
Note that 11 + 20 is a Mersenne prime exponent as well. [Luhn]
Submitted: 2002-01-04 19:16:27; Last Modified: 2008-01-30 17:28:00.
Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell