MHB Which Prime Numbers Make p^2 + 1007 Have Less Than 7 Divisors?

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The discussion focuses on identifying prime numbers \( p \) for which the expression \( A = p^2 + 1007 \) has fewer than seven positive divisors. Participants analyze the conditions under which the number of divisors of \( A \) can be calculated and the implications of those calculations. The conversation highlights the mathematical approach needed to solve the problem, including divisor counting techniques. The thread concludes with appreciation for insightful contributions, indicating a collaborative effort in problem-solving. This exploration of prime numbers and divisor functions is central to the mathematical inquiry presented.
lfdahl
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Determine all prime numbers $p$ such that the total number of positive
divisors of $A = p^2 + 1007$ (including $1$ and $A$) is less than $7$.
 
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lfdahl said:
Determine all prime numbers $p$ such that the total number of positive
divisors of $A = p^2 + 1007$ (including $1$ and $A$) is less than $7$.

P cannot be odd

reason if p is odd $p^2 $is 1 mod 8 so $p^2 +1007$ is divisible by $2^3$ so at least 4 *2 or 8 factors

so only candidate to be tested left is p =2

p =2 gives 1011 = 3 * 337 so 4 factor 1,3,337,1011

so only solution p = 2
 
kaliprasad said:
P cannot be odd

reason if p is odd $p^2 $is 1 mod 8 so $p^2 +1007$ is divisible by $2^3$ so at least 4 *2 or 8 factors

so only candidate to be tested left is p =2

p =2 gives 1011 = 3 * 337 so 4 factor 1,3,337,1011

so only solution p = 2

Thankyou, kaliprasad for your participation. Clever answer!:cool:
 

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