The famous Riemann hypothesis can be formulated in many ways. One of them is done by Farey sequences. They in turn appear as a certain features of ground states of the Falicov-Kimball model, originated in solid state physics. These interrelations will be shortly reviewed. Numerical illustrations of theorems relating FS and FK will also be presented. Moreover some (new?) phenomena, in particular presence of (apparent) self-similar structure of Farey sequences, will be demonstrated.