The least prime p that becomes composite if we add or subtract
any power of 2 less than p/2. (The next few are 3181, 3967, 4889, 8363, 8923,
...) [TT2011]. [Caldwell]
The smallest diagonal prime with distinct digits. (A diagonal prime is a prime of n^2 digits (n > 1) arranged left-right, top-down in a n-by-n matrix, where the diagonals are prime in each direction). [Loungrides]
If we examine the possible end digits of the first million primes, then "1" occurs the least, followed by "9", then
"7", with "3" occurring the most. [Honaker]
The term "factoid" was coined in 1973 by American writer Norman Mailer.