  The statistical properties of the repeating fast radio burst FRB 121102 are
investigated. We find that the cumulative distributions of fluence, flux
density, total energy and waiting time can be well fitted by the bent power
law. In addition, the probability density functions of fluctuations of fluence,
flux density and total energy well follow the Tsallis $q$-Gaussian
distribution. The $q$ values keep steady around $q\sim 2$ for different scale
intervals, indicating a scale-invariant structure of the bursts. The
statistical properties of FRB 121102 are very similar to that of the soft gamma
repeater SGR J1550-5418. The underlying physical implications need to be
further investigated.
