14 (another Prime Pages' Curiosity)
 Curios: Curios Search:   Participate: 1014 - 29 and 1014 - 27 are 14 digit twin primes. Note that 29 and 27 = 2 * 14 + 1. [Luhn] The smallest number such that (n + 3, n + 5, n + 17, n + 257, n + 65537) are all primes. Note that 3, 5, 17, 257 and 65537 are the known Fermat primes. [Russo] The sum of the first 14 primes, the first 14 composites and the first 14 non-composites are each prime. (The sums are respectively: 281, 199 and 239). These sums are also simultaneously prime for the first 208, 214, 1148, 2460, 5558, 9922, 10658, 16738, 18886, 21734, 29370 and 30850 terms. [Caldwell] The largest number for which there are as many composite numbers less than it as there are primes. [Murthy] 14 is the smallest semiprime whose reversal is a prime. [Gupta] The smallest impossible value of Euler's Phi function. [Gupta] 1!*2!*3!*4!*5!*6!*7!*8!*9!*10!*11!*12!*13!*14! + 1 is prime. [Gupta] 14^14 plus the 14th prime is prime. Other smaller examples are 1, 2 and 4. [Gupta] 14 is the first number such that it and the next number are both the product of two distinct primes (14 = 2*7 and 15 = 3*5). [Axoy] 14 = (1*4) * prime(1*4). Note that 14 is the smallest number with this property. [Firoozbakht] 1!*2!*3!*4!*5!*6!*7!*8!*9!*10!*11!*12!*13!*14! + prime(14) is prime. [Firoozbakht] The concatenation of 14, the 1st and the 4th primes, is a prime whose sum of digits is 14. Note that the product of the 1st and the 4th primes is 14. [Silva] The smallest number whose prime divisors sum to a square. [Silva] 14 = prime(1*4) + sigma(1*4). [Firoozbakht] sigma(14) = (1*4)!. [Kumar] The smallest semiprime whose distinct prime divisors sum to another semiprime. [Silva] The smallest number whose sum and difference of the digits are twin primes. [Silva] Prime(14)^14 - (14) is prime. It is curious that the digits of 14 have the same property. [Firoozbakht] The first multidigit prime difference between consecutive primes. See gaps between primes. [Silva] The only even brilliant number whose the reversal is prime. [Loungrides] (There are 15 curios for this number that have not yet been approved by an editor.) Prime Curios! © 2000-2018 (all rights reserved)  privacy statement