# 1913

This number is a prime.

The smallest prime p such that the next prime (1931) is a permutation of the digits of p. Andy Edwards introduced the name "Ormiston pairs" for these after his students at Ormiston College (in Queensland, Australia) manually inspected prime lists and found the first few cases. (An Ormiston k-tuple beginning with p is k consecutive primes each of whose digits are permutations of the digits of p.) [De Geest]

The number of letters in the chemical name for tryptophan synthetase A protein. [Byrne]

The square of 1913 and the square of its reverse have no digits in common. Are there any higher emirp pairs with this property? [Gaydos]

"The busy world, which does not hunt poets as collectors hunt for curios." F. Harrison (Webster's Revised Unabridged Dictionary, 1913)

The year in which mathematician Paul Erdős was born is an emirp. [Beedassy]

The first sedan-type automobile, a Hudson, went on display at the 13th National Automobile Show in New York in the emirp year 1913. [Green]

The smallest emirp such that 1913^2 +/- 90 are also emirps. [Bajpai]

The smallest Honaker prime (emirp) whose prime index is Sophie Germain prime. [Bajpai]

The smallest Honaker prime whose product of digits is a perfect cube (1*9*1*3=27=3^3). [Bajpai]

The only Honaker emirp concatenated from two double-digit primes. [Loungrides]

The smaller of two consecutive primes whose product of digits are equal and nonzero. [Gupta]

The difference between an emirp and its reverse is always divisible by 18. So is 3191 - 1913 = 71 * 18. But, 1913 is the smallest emirp such that the difference is 18 times an emirp. [Poo Sung]

Rudolf Diesel of diesel engine fame died suspiciously at sea in 1913. [Dillow]

(There is one curio for this number that has not yet been approved by an editor.)