Is my integer significant?
Brachylog, 5 bytes

ḍ+ᵐ&gt;₁


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How it works

ḍ+ᵐ&gt;₁                     example input: 12345678
ḍ        split in half                   [[1,2,3,4],[5,6,7,8]]
 +ᵐ      sum each half                   [10,26]
   &gt;₁    results in a decreasing list    false