26
Is this exactly how the problem was written?
That depends what number you are trying to find the factors of - all those three numbers are factors of the number 18.
4, 9, 25, 49
Assuming that 001, 080, etc are not allowed (that is a leading zero or two is not permitted), the smallest number with exactly three digits is 100. The largest number with exactly three digits is 999. So there are 999 - 100 + 1 = 900 numbers with exactly three digits.
4096 is the smallest number with exactly 13 factors. (Including 1 and itself as factors).192 is the smallest number with exactly 13 properfactors, (excluding the number itself).120 is the smallest number with at least 13 factors (it has 16 factors)To find the smallest number with exactly N factors (for example, N=12):Factor N into primes, (for example, 12= 2*2*3Subtract 1 from each of the prime factors (for example, 1,1,2)Sort them by largest first (for example, 2,1,1)Raise successive prime numbers to these powers (for example, 2^2,3^1,5^1)Multiply these together (for example: 4*3*5 = 60; 60 is the smallest number with exactly 12 factors).
There is only 1 value of N that satisfies 2029 x N has exactly three divisors: N = 2029 To have exactly three divisors, the number must be the square of a prime number. 2029 is a prime number with exactly 2 divisors (1 and 2029). Thus the only number with exactly three divisors of which two are 1 and 2029 is 20292 (= 4116841), making N = 2029.
Numbers with exactly 7 factors are of the form pqr, where p, q, and r are distinct prime numbers. To find numbers with 7 factors, you need to look for numbers that can be expressed as the product of three different prime numbers.
you can by starting with one and ask yourself, is this a factor? Then two, then three ect....
Every prime number has exactly two factors. One of the factors is ' 1 '.The other factor is the number itself. If the number has any more factors,then it's not a prime number.If someone gives you a number, guarantees that it's definitely a prime number,and asks you to find the factors, you know the answer immediately. There aretwo factors. One of the factors is ' 1 ', the other factor is the number itself, andthere are no more factors.
3 x 5 x 7 = 105
Start looking for factors; you already know that 1 is a factor, and that the number itself is a second factor (unless the number is 1). As soon as you find a factor that is neither 1 nor the number itself, the number is composite. If you find exactly two factors, the number is prime. If the number has only one factor, the number is 1, which is neither prime nor composite.