159

This number is a composite.

+ 159 = 3 x 53, and upon concatenating the prime factors, we have a peak palindrome, 353, which is itself a prime. [Trotter]

+ Deshouillers (1973) showed that all integers are the sum of at most 159 prime numbers.

+ The last 159 digits of 157^158 is prime. [Gupta]

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