Yu Jianchun, who works for a parcel delivery company, said he'd always had a passion for numbers and has created an alternative method to verify Carmichael numbers.
His solution amazed academics, who said his proof was much more efficient than the traditional one.
"It was a very imaginative solution," said Cai Tianxin, a math professor at Zhejiang University.
"He has never received any systematic training in number theory nor taken advanced math classes. All he has is an instinct and an extreme sensitivity to numbers."
Carmichael numbers are sometimes described as "pseudo primes" -- they complicate the task of determining true prime numbers, which are divisable only by 1 and itself. They play an important role in computer science and information security.
Yu worked on his proof during his free time while building a new home in his village last year.
"I was overwhelmed with joy, because my solution was completely different to the classic algorithm," said Yu.
William Banks, a mathematician at the University of Missouri, who works with Carmichael numbers said, if verified, an alternative proof would be an exciting discovery for his field.
He said that the only construction of an infinite family of Carmichael number was done by academics 20 years ago.
"There have been additional theoretical results in this area -- including several by myself and my co-authors -- but these are all variations on a theme," he said.
Yu presented his proof -- along with solutions to four other problems -- to the public on June 13 at a graduate student seminar on the invitation of Cai.
However, it took Yu more than eight years of writing letters to prominent Chinese mathematicians to get any recognition for his talent.
Cai, the professor, says he will include Yu's solution in an upcoming book.