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193 is the natural number between 192 and 194. It is also a prime number.

In mathematics

193 is a prime number, the only odd prime p known for which 2 is not a primitive root of 4p² + 1.^[1] 193 is a cuban prime, and a twin prime with 191. It is also a happy and lucky prime. 193 is a Proth prime as it is 3 × 2⁶ + 1. It can be written as the difference between the product and the sum of the first four primes.

References

1. ^ E. Friedman, "What's Special About This Number" Accessed 2 January 2006 and again 15 August 2007. "193 is the only known odd prime n for which 2 is not a primitive root of 4n² + 1"

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