1409

This number is a prime.

+ 1409 contains no prime digits. π(1409) equals 223 and contains all prime digits. π(223) equals 48 with no prime digits. Note that 1409 is the smallest prime with this property. [Punches]

+ The smallest emirp whose digits are distinct square digits. Note that its reversal is the largest such emirp. [Loungrides]

+ Your best chance of being born in a prime number year in the past millennium was to have been born in the 15th century (17 prime number years, from 1409 to 1499). [Tammet]

+ The first emirp p such that 2p+1, 3p+2, and 4p+3 are prime. [Loungrides]

+ The only known number whose 8th power can be written as the sum of eight 8th powers. [Gudipati]

+ The smallest emirp such that the emirp pair are PIPs [Prime-Indexed Primes]. E.g., 1409 is the 223rd prime and 9041 is the 1123rd prime. Both 223 and 1123 are prime. Emirpips? [Green]

+ Each of the states North Dakota, Rhode Island, and Wyoming have just one area code for the state and they are 701, 401, 307, respectively, and each is a prime. Curiously, the sum of the three codes is an emirp (which happens to be a twin prime). [Green]

+ The smallest prime p such that 2p+1, 3p+2, 4p+3 are prime. [Loungrides]

+ The first multidigit prime (emirp) in the sequence of pentanacci numbers whose predermined terms are the odd digits. [Loungrides]

+ The 46th Sophie Germain prime (1409) divides the sum of the first 46 primes (4227). [Gaydos]

+ The smallest emirp p with a prime index such that reversal(p) is also a prime with a prime index. [Sariyar]

+ The first composite Fibonacci "hole" occurs at F1409.

Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell