8444

8444 = 2 x 2 x 2111. It is a composite number such that its prime factors contain only the digits 1 or 2 (A036302).

8444 is equal to the square of the sum of the first 9 primes minus the sum of the squares of the first 9 primes (A065595).

For 8444, each digit (a composite) minus 1 is a prime, the sum of the digits minus 1 (19) is a prime, and the difference of digits (in absolute value) minus 1 is prime (A058229).

8444 divides 75¹⁰ - 1.

8444 is 33422 in base 7. It also uses the same digits in base 5 (232234).

Source: On-Line Encyclopedia of Integer Sequences