Unity Prefabs Taking too much size

So my project was just fine under 70mb apk size, after I removed a couple of unused assets and scripts and rebuilt size raised up to 118mb apk.
After checking build report I got Other assets were taking huge size, I didn't know what those were, so I checked with size explorer and here is what i got:
Build Report
Uncompressed usage by category (Percentages based on user generated assets only):
Textures 45.5 mb 6.7%
Meshes 9.2 mb 1.4%
Animations 19.0 mb 2.8%
Sounds 2.5 mb 0.4%
Shaders 4.8 mb 0.7%
Other Assets 549.3 mb 81.0%
Levels 4.5 mb 0.7%
Scripts 2.5 mb 0.4%
Included DLLs 11.3 mb 1.7%
File headers 29.4 mb 4.3%
Total User Assets 677.9 mb 100.0%
Complete build size 941.5 mb
Used Assets and files from the Resources folder, sorted by uncompressed size:
32.2 mb 3.4% Assets/Prefabs/Letters/M.prefab
32.2 mb 3.4% Assets/Prefabs/Letters/W.prefab
32.2 mb 3.4% Assets/Prefabs/Letters/B1.prefab
32.2 mb 3.4% Assets/Prefabs/Letters/Y.prefab
28.1 mb 3.0% Assets/Prefabs/Letters/H1.prefab
28.1 mb 3.0% Assets/Prefabs/Letters/Q.prefab
28.1 mb 3.0% Assets/Prefabs/Letters/A1.prefab
24.1 mb 2.6% Assets/Prefabs/Letters/R.prefab
24.1 mb 2.6% Assets/Prefabs/Letters/E1.prefab
24.1 mb 2.6% Assets/Prefabs/Letters/O.prefab
24.1 mb 2.6% Assets/Prefabs/Letters/D1.prefab
24.1 mb 2.6% Assets/Prefabs/Letters/G1.prefab
24.1 mb 2.6% Assets/Prefabs/Letters/N.prefab
20.1 mb 2.1% Assets/Prefabs/Letters/Z.prefab
20.1 mb 2.1% Assets/Prefabs/Letters/S.prefab
20.1 mb 2.1% Assets/Prefabs/Letters/F1.prefab
20.1 mb 2.1% Assets/Prefabs/Letters/T.prefab
20.1 mb 2.1% Assets/Prefabs/Letters/U.prefab
20.1 mb 2.1% Assets/Prefabs/Letters/P.prefab
16.1 mb 1.7% Assets/Prefabs/Letters/V.prefab
16.1 mb 1.7% Assets/Prefabs/Letters/J.prefab
16.1 mb 1.7% Assets/Prefabs/Letters/C1.prefab
12.1 mb 1.3% Assets/Prefabs/Letters/L.prefab
8.1 mb 0.9% Assets/Prefabs/Letters/I1.prefab

The prefabs have simple cubes and walls with a single material and texture which is applied to all.
Any idea what's going on?

 

That does seem big. For a given asset, what are some details about the texture it's using?

 

Textures are compressed to 512. Also Project started taking a long time to load and became memory hungry.

 

Can't you just use Unity's Profiler and Memory Profiler to measure a build/player, not the game playing in the editor, what's in memory and how much each of the loaded stuff costs?

 

So, I fixed it. Issue was that each prefab had a couple of nested prefabs with hundreds of public prefab references.
Thanks anyways.