# 409

This number is a prime.

Just showing those entries submitted by 'Gaydos': (Click here to show all)

The smallest prime number that has a digital root of 4. All other digital roots are represented by smaller primes except for 6 and 9 which cannot be digital roots of primes. [Gaydos]

The smallest prime number that becomes a pandigital prime number (2561387420489) when each of its digits d is replaced by d^d. [Gaydos]

The smallest Cyclops prime that does not become a smaller prime when its zero is removed. [Gaydos]

The highest point in Washington DC is 409 feet above sea level. [Gaydos]

409 and the 409th palindrome (31013) are both Cyclops primes. [Gaydos]

(There are 4 curios for this number that have not yet been approved by an editor.)

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