Nouri, who also wore the number, made his senior debut in 2016-17 before his playing career ended prematurely after he suffered cardiac arrest in a pre-season friendly in Austria.
Despite being revived on the pitch and rushed to a hospital, Nouri suffered serious and permanent brain damage.
“This is a special thing for me because of my good friend Abdelhak Nouri,” Van de Beek, who joined United from Ajax on a five-year contract on Wednesday, told the club’s website.
“He had a heart attack... I’m really close with his family and his brother is one of my best friends and I talk a lot with them. So I decided to take his old number on my shirt and I want to get good memories with this number.”