The young Belgium international inherits the shirt that was for so long owned by legendary midfielder Ryan Giggs, while Luke Shaw takes the No.3 and Ander Herrera is No.21
The Belgium international inherits the number vacated by the recently retired Ryan Giggs, who ended one of the most decorated ever playing careers to become Louis van Gaal's assistant manager this summer.
New midfield signing Ander Herrera takes the No.21, while £30m teenager Luke Shaw is handed the No.3 as he succeeds Juventus-bound Patrice Evra.
The club's legendary No.7 shirt remains vacant, having been given up by Ecuadorian winger Antonio Valencia over a year ago, and could yet be filled by transfer target Juan Cuadrado.
There is also no No.9 listed by Van Gaal's side, with newly confirmed captain Wayne Rooney keeping his No.10.
SQUAD NUMBERS IN FULL:
1. De Gea; 2. Rafael; 3. Shaw; 4. Jones; 6. Evans; 8. Mata; 10. Rooney; 11. Januzaj; 12. Smalling; 13. Lindegaard; 14. Hernandez; 16. Carrick; 17. Nani; 18. Young; 19. Welbeck; 20. Van Persie; 21. Herrera; 22. Powell; 23. Cleverley; 24. Fletcher; 25. Valencia; 26. Kagawa; 28. Anderson; 29. Zaha; 30. Varela; 31. Fellaini; 34. Lawrence; 35. Lingard; 36. Vermijl; 38. M Keane; 39. Thorpe; 40. Amos; 41. James; 42. Blackett; 45. Petrucci; 46. Rothwell; 48. W Keane; 49. Wilson; 50. Johnstone