159

159 = 3 x 53. Concatenating the prime factors gives 353, which is a peak palindrome and a prime number.

In 1973, Jean-Marc Deshouillers showed that all integers are the sum of at most 159 prime numbers.

159 is a number that cannot be written as a sum of three squares.

159 x 48 = 7632 uses all the digits from 1 to 9 once.

135², 159², and 285² use the same digits: 135² = 18225; 159² = 25281; and 285² = 81,225.

The chemical element terbium has one stable isotope, which has as mass number of 159.

Source: Prime Curios!