# 35

This number is a composite. The number of pairs of twin primes less than 1000. The first composite number occurring in Pascal's Triangle whose digit reversal is prime. The product of 35 and 36 has the same prime factors as the product of 4374 and 4375. [Guy] 35 is the smallest product of twin primes of the form (4*k+1, 4*k+3), k>0. [Zumkeller] The number of known even numbers which are not the sum of two twin primes (coming from the same pair or not). [Capelle] 35 can be written as a sum of odd primes in 35 ways, and as a sum of primes in 35 * 5 ways. [Hartley] 35 = 23 + 33, i.e., the sum of the cubes of the first two primes. Factor 35 and get the third and fourth primes. [Mizuki] 35 is the smallest number formed from two odd primes. Its prime factors are 5 and 7. Note that its digital sum (8) and digital product (15) are each one less than perfect squares. No prime number greater than 3 fits this category. [Storms] The smallest concatenation of two consecutive primes divisible by the next prime. [Silva] The smallest number formed from twin primes and equal to the product of twin primes. [Silva] A photograph printed in the popular 5 x 7 inch 'twin-prime' format has a semiprime area equal to 35 square inches. [Green] The only known number that is concatenation of two successive primes that is divisible by one of them. Are there more? [Sariyar]

(There are 7 curios for this number that have not yet been approved by an editor.)