561
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Summary
Factorization
The factorization into primes is:
Properties and families
| Property or family | Parameter values | First few numbers satisfying the property |
|---|---|---|
| Carmichael number (also called absolute pseudoprime) | first Carmichael number | 561, 1105, 1729 |
| Poulet number ([[Fermat pseudoprime to base 2) | second Poulet number | 341, 561, 645 |