from this page.
it says :
All textures should have dimensions that are powers of two (32, 62, 1024, 2048).
If you want to make use of mipmaps, your texture should not exceed 4096px (4K).
Keep in mind that some GPUs have hardware limits of 8192px (8K).
Epic authors most of its texture content at 2048px.
but “62” is not a correct number . it shuould be “64” .