## Task 1 - 130811

Determine all possibilities to specify a four-digit odd (natural) number $z$ such that it has the following properties:

(1) The number $z$ has four different digits.

(2) The product of the second and the third digit of $z$ is 21 times as large as the product of the first and the fourth digit.

(3) The smallest of the digits of $z$ is in the first place, and the largest is in the second place.