Amicable numbers are pairs of positive integers where each number equals the sum of the proper divisors of the other number. Proper divisors are all the positive divisors of a number except the number itself.
The smallest pair of amicable numbers is 220 and 284:
Amicable numbers may not appear in everyday calculations, but they play an important role in mathematics. They help us understand how numbers relate through their factors and divisors, sharpen pattern recognition, and build strong logical thinking. Often used in number theory, teaching, and programming practice, amicable numbers remind us that some parts of mathematics exist not for direct application, but to train the mind to think clearly and deeply.
Goldbach’s conjecture is one of the oldest unsolved problems in mathematics.
Any even number greater than 2 can be written as the sum of two prime number.
Every odd whole number greater than 5 can be written as the sum of three primes.Â
Goldbach’s conjectures
Goldbach, a Prussian mathematician(1690-1764)
On 7 June 1742, Goldbach wrote a letter to the mathematician Euler in which he proposed the conjectures he found.
Euler responded back on 30 June 1742 as
Every integer greater than 2 is a sum of two primes, I regard this as a completely certain theorem, although I cannot prove it.
Euler
Though the Goldbach’s conjecture looks simple to understand, it has not yet been proved.
In the modern times, the conjectures proposed by Goldbach is identified as weak or strong Goldbach conjecture.
STRONG GOLDBACH CONJECTURE
Any even whole number greater than 2 can be written as the sum of two prime number.
WEAK GOLDBACH CONJECTURE
Every odd whole number greater than 5 can be written as the sum of three primes.Â
In 2013, Harold Helfgott, a Peruvian mathematician released two papers claiming the proof of Goldbach weak conjecture and The proof was accepted for publication in the Annals of mathematics series in 2015, and has been undergoing further review and revisions.
In March 2000 the publishers of the book ‘Uncle Petros and Goldbach’s conjecture (Bloomberg in the USA and Faber and Faber in the UK) offered a prize of one million dollars for anyone who could prove the Goldbach’s conjecture
Any even whole number greater than 2 can be written as the sum of two prime number.
The prize was kept open for two years, but nobody claimed it.