Is that a hidden number ? What a visual headset that puts your brain to the test!

Answer

The drawing contains the following figures:

6
8
2
4

Reading from top to bottom, the number is:

6824

It’s possible that some people think they see other digits by interpreting certain traits differently. Although, in this illustration, the digits clearly drawn and superimposed are 6, 8, 2 and 4, which gives 6824.