The greatest one-digit number is 9. Therefore the 3 is its hundreds digit.
The tens place is twice of 3, which is 6.
The ones digit is four times the half of the hundreds digit, which again is 6.
The three numbers in the thousands place is the product of the those three numbers, which is 3 x 6 x 6 = 108
Therefore the number is 108366
Is this right? Hope this helps :))