97

This number is a prime.

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

Carla Kik © 2004
+ The smallest prime (emirp) equal to the sum of first n odd composite numbers (n = 5), i.e., 97 = 9 + 15 + 21 + 25 + 27. [Loungrides]

+ The larger of only two double-digit primes that remain prime when inserting one, two, three or four zeros between the digits. The other is 71. Note that both of them are emirps. [Loungrides]

+ The smallest prime (the only emirp) that is the sum of the reversals of two consecutive double-digit composite numbers, i.e., (39, 40). [Loungrides]

+ The only double-digit prime p such that 100-p and 100+p are both primes. [Loungrides]

+ The smallest number n, (it is also prime and emirp), such that the product of first n positive even numbers minus 1 is a prime greater than a googol. Note that the product of first n even numbers minus 1 is given by the form 2^n*n!-1, where n is the number of even numbers. May we call the primes of this form, “almost evenian primes”? [Loungrides]

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