Browse · MathNet
Print55rd Ukrainian National Mathematical Olympiad - Fourth Round
Ukraine number theory
Problem
Find all integer , such that:
Solution
If integer number satisfies the given condition, then can be presented as product of four pairwise distinct integers. Since the integer divisors of this number are only , and , we have that sought-for divisors are and . Indeed, if the absolute value of one of divisors is equal to then others are not less than by absolute value, a contradiction. Since is the biggest factor, it should be equal to . Also we see that satisfies the condition of the problem.
Final answer
2015
Techniques
Techniques: modulo, size analysis, order analysis, inequalitiesPolynomial operations