According to today's headline data, carmichael number, also known as absolute pseudo prime number, was first discovered by American mathematician Carmichael in 19 12, and there are only 255 positive integers within 100 million. Carmichael's numbers start with 56 1, 1 105,1729,2465 ... They play an important role in computer science and information security. The criterion of Kerr number has always been a hot topic for number theory enthusiasts, so carmichael, an American mathematician, published a table of pseudo prime numbers within 1 100 million.