The volume of the observable universe is approximately 4e80 meters cubed. Assuming the average tangerine is about 0.065 meters in diameter (or 0.0325 in radius), and is a perfect or near-perfect sphere, we end up with a volume of 1.43793e-4 meters cubed (0.000143793 meters cubed). Divide the volume of the observable universe (4e80 m^3) by the volume of a tangerine (1.43793e-4 m^3), and we get 2.78177658e84 tangerines.
2.78177658e84 is equal to 2,781,776,580,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 tangerines.