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 5 curios for this number that have not yet been approved by an editor.)
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