1069

This number is a prime.

The smallest four-digit emirp with distinct digits. [Capelle]

The mouth of a prime volcano (truncated pyramid).

          1069 
         310693
        33106933
       3331069333
      333310693333

1069 = 1 + 1*3 + 1*3*5 + 1*3*5*7 + 1*3*5*7*9. [Silva]

The first "double" super-2 emirp, i.e., an emirp p such that 2*p^2 contains twice 2 consecutive 2's in its decimal representation (2*p^2=2285522). [Loungrides]

The smallest distinct-digit 4-digit prime (emirp) such that the sum of the powers of its digits with exponents equal to their bases, is also prime (emirp), i.e., 1^1+0^0+6^6+9^9 = 387467147. [Loungrides]

The smallest emirp that is a concatenation of three distinct brilliant numbers (10, 6, 9). [Loungrides]

1069 is the smallest emirp which is a sum of multidigit primes beginning and ending with the digit three, i.e., 313+373+383=1069. [Loungrides]

The smallest four-digit prime requiring seven steps to reach its fixed point under Kaprekar's process. [Honaker]

The prime 1069 remains prime for D = 0 to 2 in 1D0D6D9 producing the primes 1000609, 1101619, 1202629. [Rivera]

1069 and the next prime number are the smallest pair of consecutive primes with square sums of digits. [Gaydos]

Astronomers have found a planet (Wolf 1069B) which is the most Earth-like to date. It is a rocky world with a temperature of 13°C, however it is 31 light-years from us. [Homewood]