Question

The integer 561 is a Carmichael number.

(a) True

(b) False

This question was posed to me by my college professor while I was bunking the class.

Query is from Applications of Number Theory in chapter Number Theory and Cryptography of Discrete Mathematics

Answer 1

Correct answer is (a) True

The explanation is: By using the Fermat’s theorem, it follows that b^560 is congruent to 1 (mod 561).