divides for all integers iff is squarefree and for all prime divisors of . Carmichael numbers satisfy this criterion.

Borwein, D.; Borwein, J. M.; Borwein, P. B.; and Girgensohn, R. "Giuga's Conjecture on Primality." Amer. Math. Monthly 103, 40-50, 1996.

CITE THIS AS:

Weisstein, Eric W. "Korselt's Criterion." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/KorseltsCriterion.html