What is a Trinity Number™?

_{This is inspired by the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles, and the Number™ series.}

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If a number conforms to a special rule, I call it a Trinity Number™. Use the examples below to find the rule.

The puzzle satisfies the series’ inbuilt assumption that each number can be tested for whether it is a Trinity Number™ without relying on the other numbers. These are not the only examples of Trinity Numbers™; many more exist.

What is the special rule these numbers conform to?

CSV version:

Trinity Number™, Not Trinity Number™
666, 777
1988, 2020
2048, 64
404, 200
4096, 1024
1048576, 2097152
89, 97
20200520, 20201225

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Hint: