70

This number is a composite.

+ The reversal of 270 is prime. [Somer]

+ The prime formed from the reversal of 270 has a digit sum of 70. [Patterson]

+ Any composite number n has a witness (i.e., does not pass Miller's test) less than 70(ln n)^2 if the Riemann hypothesis is true.

+ All the primes in the 70's are emirps. [Green]

(There is one curio for this number that has not yet been approved by an editor.)

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