You would say "el veinticinco de enero". Remember that the names of the months are not capitalized in Spanish.
su cumpleaños es el 1 de abril
Abril.
El primero de abril
You can say "No Abra hasta el 4 de abril". Note that the names of the months are not capitalized in Spanish.
The number one in Spanish is uno.
Álgebra 1
1 25
abril. Note it is not normally capitalized, except at the beginning of a sentence.
"20 de abril"
The month "April" is abril in Spanish.
Episode
Vacaciones de Semana Santa Vacaciones de abril