According to the meaning of the question, the single digit is a hundred digits: 2×2=4 (times);

Let the hundredth digit be x, then the decimal digit is 2x and the unit digit is 4x, and the equation can be obtained:

x+2x+4x= 14

7x= 14，

x=2。

Then these ten digits are: 2 × 2 = 4;

Number of units: 2× 4 = 8.

That is, Xiao Ming's admission ticket number is: 248.

So the answer is: 248.