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+ The smallest palindromic prime of the form n*phi(n) - 1. [Russo]

+ The reversal of fib(191) is prime.

+ If the ancient Hebrew and Greek coding scheme (i.e., 1, 2, 3, ..., 10, 20, 30, ... 100, 200, 300, etc.) is applied to the English letters, then "PALINDROMES ARE FUN" yields an anagram of 191 that is also prime, i.e., 911. [Strachan]

+ The last three digits of M(11213). [Griffin]

+ A prime number of spaces are formed if we choose n = 191 distinct points on a circle so that no three of the chords that join them are concurrent. In general, the number is g(n) = (n^4 - 6n^3 + 23n^2 - 18n + 24)/24.

+ The Major League Baseball record for most runs batted in (RBIs) in a single season is 191, set by Hack Wilson of the Chicago Cubs in 1930. [Litman]

+ American Airlines Flight 191, which crashed on May 25, 1979, remains the deadliest airplane accident on U.S. soil in terms of the total number of aircraft occupants killed.

+ The smallest multidigit palindromic prime that yields a palindrome when multiplied by the next prime: 191 * 193 = 36863. [Russo]

+ 191 is the smallest prime such that the sum of the reciprocals of the primes less than or equal to it begins with the digits of the next prime. Thus, 1/2 + ... + 1/191 = 1.9337.... [Rupinski]

+ 149 and 191 are both prime. So are both 149*2^191+1 and 191*2^149+1. [Hartley]

+ The larger of the first occurrence of two successive primes using no prime digits. [Murthy]

+ When the palindromic prime 191 is doubled and one is added to this result, the resulting number is yet another palindromic prime. [Dobb]

+ The values of the most popular United States coins currently in circulation (silver dollar, half-dollar, quarter, dime, nickel, and penny) sum to 191 cents. [Patterson]

+ The smallest palindromic prime p such that neither 6p - 1 nor 6p + 1 is prime. [Necula]

+ The smallest palindromic prime whose sum of digits is a multidigit palindromic prime. [Gallardo]

+ Multiply the even composites 4*6*8 - 1 and get 191 using 3 terms and 2 multiplications. Do the same + 1 and get 193 -- the first set of twin primes using this process. [Haga]

+ 191 has a prime number (19) of letters in its English name "ONE HUNDRED NINETY-ONE." Note that 191 contains 19 if read from the right or left. [Post]

+ The smallest prime in a set of four consecutive multidigit primes, i.e., {191, 193, 197, 199}, whose sum of digits (i.e., 11, 13, 17, 19) is another set of four distinct primes. [Gupta]

+ A palindromic prime whose square is a distinct-digit number whose first two digits, central digit, and last two digits, are perfect squares.

+ There are 191 orientable octahedral manifolds. [Beedassy]

+ This number turned upside down forms the first three digits in the decimal expansion of the golden ratio (phi = 1.618...). [Meiburg]

+ First member of a pair of Sophie Germain primes which are palindromic: 191*2+1 = 383. [Silva]

(There are 8 curios for this number that have not yet been approved by an editor.)




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