Difference between revisions of "2006 Cyprus MO/Lyceum/Problem 24"

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==Problem==
 
==Problem==
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The number of divisors of the number <math>2006</math> is
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A. <math>3</math>
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B. <math>4</math>
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C. <math>8</math>
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D. <math>5</math>
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E. <math>6</math>
  
 
==Solution==
 
==Solution==
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<math>2006 = 2 \cdot 17 \cdot 59</math>. A number has <math>(m_1 + 2)(m_2 + 1) \cdots (m_n + 1)</math> divisors, where <math>N = p_1^{m_1} \cdots p_n^{m_n}</math>, with prime <math>p_i</math>. Thus <math>2006</math> has <math>(1+1)^3 = 8\ \mathrm{(C)}</math> divisors.
  
 
==See also==
 
==See also==
 
{{CYMO box|year=2006|l=Lyceum|num-b=23|num-a=25}}
 
{{CYMO box|year=2006|l=Lyceum|num-b=23|num-a=25}}
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[[Category:Introductory Algebra Problems]]

Revision as of 17:26, 15 October 2007

Problem

The number of divisors of the number $2006$ is

A. $3$

B. $4$

C. $8$

D. $5$

E. $6$

Solution

$2006 = 2 \cdot 17 \cdot 59$. A number has $(m_1 + 2)(m_2 + 1) \cdots (m_n + 1)$ divisors, where $N = p_1^{m_1} \cdots p_n^{m_n}$, with prime $p_i$. Thus $2006$ has $(1+1)^3 = 8\ \mathrm{(C)}$ divisors.

See also

2006 Cyprus MO, Lyceum (Problems)
Preceded by
Problem 23
Followed by
Problem 25
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