Smith Number Checker
Check whether a composite number's digit sum equals the digit sum of its prime factors with multiplicity.
Description
Check whether a composite number's digit sum equals the digit sums of its prime factors with multiplicity.
Smith Number Checker check whether a composite number's digit sum equals the digit sums of its prime factors with multiplicity.
Use this for recreational number theory, factorization exercises, sequence validation, and testing known Smith numbers such as 22.
When to use Smith Number Checker
Use this for recreational number theory, factorization exercises, sequence validation, and testing known Smith numbers such as 22.
How it works
The tool trial-divides the value, adds decimal digit sums for every prime factor occurrence, and requires equality with the original digit sum and more than one prime factor occurrence.1
Interpreting the result
Keep the input units, direction conventions, encoding, and ordering rules visible when reusing the result. Preserve the full returned value for downstream calculations and round only for presentation.
Assumptions and limitations
Prime numbers are excluded by definition. The bounded input keeps trial division responsive and this tool does not return the factorization itself.
References
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The On-Line Encyclopedia of Integer Sequences — OEIS Foundation