  The use of quantality is discussed in the case of nuclei and other many-body
systems such as atomic electrons. This dimensionless quantity is known to
indicate when a many-body system behaves like a crystal or a quantum liquid.
Its role is further analyzed, showing the emergence of a fundamental
lengthscale, the limit radius, which corresponds to the hard-core of the
nucleon-nucleon interaction in the case of nucleons, and to a value close to
the Bohr radius in the case of atomic electrons. The occurrence of a cluster
phase in nuclei is analyzed using the quantality through its relation to the
localization parameter, allowing for the identification of both the number of
nucleons and the density as control parameters for the occurrence of this
phase. The relation of the quantality to the magnitude of the interaction also
exhibits a third dimensionless parameter, monitoring the magnitude of the
spin-orbit effect in finite systems, through the realization of the pseudo-spin
symmetry. The impact of quantality on the spin-orbit effect is compared in
various many-body systems. The role of quantality in the relative effect of the
binding energy and the shell one is also analyzed in nuclei. Finally,
additional dimensionless quantities are proposed from the generalization of the
quantality. Nuclei are found to be exceptional systems because all their
dimensionless quantities are close to the order of unity, at variance with
other many-body systems.
