This number is a composite.
The concatenation of the prime number 11 with itself.
1111 equals 112 + 122 + 132 + 142 + 152 + 162. [De Geest]
1111 = 11 * 101 in both base 10 and base 2. Notice the factors (11 and 101)
are palindromic primes in both of these bases. [Shafer]
The sum of the digits of the first 100 primes. [Wilson]
The smallest tetradic semiprime with tetradic factors. [Capelle]
The smallest repunit number with anti-Yarborough prime factors (101 × 11) whose concatenation (10111) is prime. [Loungrides]
(There are 5 curios for this number that have not yet been approved by an editor.)
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