We provide a comprehensive statistical analysis of the sample entropy of peak and time‐integrated geomagnetic events in 2001–2017, considering different measures of event strength, different geomagnetic indices, and a simplified solar wind‐magnetosphere coupling function
P*. Our investigations reveal the existence of significant correlations between the entropies of
Dst,
ap, and
P*, and between such entropies and event strengths, as well as good correlations between peak levels of solar wind‐magnetosphere coupling and ring current (
Dst) and
ap entropies, suggesting a potential predictability of significant
Dst and
ap events on the basis of appropriate functions of
P*. Sensibly weaker correlations are found with
AE entropy. We further show the presence of several significant entropy correlations between geomagnetic indices, solar wind‐magnetosphere coupling, and trapped or precipitated energetic electron and ion fluxes measured by geostationary and low Earth orbit satellites in the outer radiation belt during the same periods. Entropy correlations between
Dst and trapped or precipitated 30‐ to 80‐keV ion fluxes at low
L and between
AE and trapped 40‐keV electron fluxes at geostationary orbit correspond well with ring current properties and substorm‐induced injections, respectively. Entropy correlations between
ap and precipitation rates of energetic ion and electron fluxes demonstrate the sensibility of
ap index entropy to both low‐energy (5–30 keV) electron injections and ring current. The stronger entropy correlation between solar wind‐magnetosphere coupling and
ap than
AE likely stems from the more stochastic behavior of electron injections and fast losses near geostationary orbit.