Other tidbits about prime numbers (from the Prime Curios site)
- A emirp is a number that is also prime when the digits are written in reverse order.
- 1234567891010987654321 is a palindromic prime. (As Matt correctly pointed out to me, this is not a strict palindrome…unless you count like so: “one, two, three, four, five, six, seven, eight, nine, ten, ten, nine…” Also, the Prime Curios site listed this number as a “Smarandache generalized palindromic prime”. I have no idea how this differs from a non-Smarandache generalized palindromic prime; I’ll leave that as an exercise for the interested reader.)
- A megaprime is a prime number with at least 1,000,000 digits.
- 200 is the smallest number which cannot be turned into a prime number by modifying one of the digits.