- No digit appears more than once.
- The sum of the last four digits equals twice the sum of the first two.
- The first two digits form a prime number when concatenated.
- Digits 2 and 3 also form a prime.
- Digits 3 and 4 also form a prime.
- Digits 4 and 5 also form a prime.
- Digit 5 itself is also a prime.
- All six digits add up to 33.

From Mensa Puzzle Calendar 2018 by Fraser Simpson, Workman Publishing, New York. Puzzle for October 9.