Fujifilm Z900EXR has a 16.0MP 1/2" (6.4 x 4.8 mm ) sized EXRCMOS sensor and features EXR processor. On the other hand, Kodak Astro Zoom AZ651 has a 21.0MP 1/2.3" (6.17 x 4.55 mm ) sized CMOS sensor . Kodak Astro Zoom AZ651's sensor provides 5MP more than Fujifilm Z900EXR's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the Z900EXR and Astro Zoom AZ651 sensor size comparison.
Fujifilm Z900EXR and Kodak Astro Zoom AZ651 have almost the same sensor size so none of them has any significant advantage over other in this area.