On p37 in Keller's Learn to Read Latin:
The infinitive is an abstract verbal noun in the neuter singular. It is indeclinable; that is, although it is a noun, it does not have case endings, and it has limited syntactic functions. The infinitive has the verbal properties of tense (present, perfect, or future) and voice (active or passive). As noted in Section 7, the second principal part of every verb is the present active infinitive and is regularly translated "to ." For example: movere, "to move."
Does it say that an infinitive as a noun is neuter in gender?
But on p269, is it correct that the perfect passive infinitives and the future active infinitives are periphrastics, i.e. have compound forms? Does the participle in such a periphrastic have different forms for different genders, so does such an infinitive have different forms for different genders? For example,
perfect passive infinitives: vocatus, a, um esse,
future active infinitives: vocaturus, a, um esse.
Are "vocatus, a, um esse" three infinitives with genders masculine, feminine, and neuter respectively? So can an infinitive have gender other than neuter? If all the three infinitives are neuter, when shall I use which of the three?
Or are "vocatus, a, um esse" three forms of the same infinitive, and the forms have genders masculine, feminine, and neuter respectively?