Welcome to the ODK forum, @Yassine_ADJEI-TOURE! We're glad you're here. When you get a chance, please introduce yourself on this forum thread. I'd also encourage you to add a picture as your avatar because it helps build community!
Is the household number something that is preassigned to the household? Could you print a barcode or QR code ID card for the household and scan it during the survey?
Or are you looking for a unique identifier number for each household? Some conversations that may be of interest: