Escribir ⇢ Escrito
El detective llegó al hotel con el número de la habitación escrito en un papel. El hotel estaba en una calle muy adjetive (transitada).
Remember that the impersonal forms are those that do not coincide in gender and number with the subject that performs the action.
The impersonal forms are:
- Infinitive
- Gerund
- Participle ⇢ In this case.
Remember that the participle is a verbal form while an adjective always describes a quality of the noun, always agreeing in gender and number with the noun it accompanies.