The correlation functions and energy spectra of clusters of carbon nanotubes with the (5, 5) chirality that consist of 30, 50, 70, 90, and 190 atoms have been obtained in terms of the Hubbard model. It has been assumed that, taking into account the Hubbard correlations, carbon nanotubes with the (5, 5) chirality should be semiconductors with a band gap of ∼1 eV. This contradicts the generally accepted concept, according to which carbon nanotubes with the (m, n) chirality should be metals if the difference in the chirality indices m − n is multiple to three or equal to zero. The results obtained have been compared with experimental data on electrical conductivity and scanning tunneling microscopy of carbon nanotubes.