1867

This number is a prime.

There are only 1867 different summing equalities for numbers 1 to 11 where no value is used more than once: 1+2=3, 1+3=4, 2+3=1+4, etc.

1867 is the smallest prime that can be expressed as the sum of distinct Fibonacci numbers in 42 different ways.

1867 is the smallest prime that is the sum of 44 consecutive composite numbers: 1867 = 14 + 15 + 16 + 18 + 20 + ... + 68 + 69 + 70.

1867 = 284th prime + 284th composite: 1867 = 1559 + 308.

Concatenating the prime previous to 1867 with itself, is prime, i.e., 18611867 is prime. [Noll]