9514 1404 393
Answer:
- 45 has divisors 1, 3, 5, 9, 15, 45
- 75 has divisors 1, 3, 5, 15, 25, 75
Explanation:
The number of divisors a number has is the product of the powers of its prime factors, each increased by 1. If a number has 6 factors, it will be either the 5th power of an odd prime, or the product of two odd primes, one of them being squared.
Examples:
243 = 3^5 has 5+1 = 6 divisors: 1, 3, 9, 27, 81, 243
45 = 3^2×5 has (2+1)(1+1) = 6 divisors: 1, 3, 5, 9, 15, 45
75 = 3×5^2 has (1+1)(2+1) = 6 divisors: 1, 3, 5, 15, 25, 75
331169 = 61^2×89 has (2+1)(1+1) = 6 divisors: 1, 61, 89, 3721, 5429, 331169