Do I need a VAT number for money earned through ads or app sales (Belgium)

Question

I'm wondering if you need a VAT/BTW number in Belgium for money you could earn by doing one or both of the following:

• Creating an Android/IOS app (free time) and sell it
• Earn ad revenue (e.g. Admob) through ads on your own website/apps.

Or does this all depend on the amount you earn? E.g. if it would be less as € 500,00 a year.