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(Relationship with other odd numbers)
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*The odd number previous to 69 is 67. 67 is a prime number.
 
*The odd number previous to 69 is 67. 67 is a prime number.
 
**67 and 71 are four numbers apart; therefore, they are cousin primes.
 
**67 and 71 are four numbers apart; therefore, they are cousin primes.
*The odd number previous to 67 is 65. 65 is not a prime number.
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*The odd number previous to 67 is 65. 65 is not a prime number. It is divisible by 5.
 
===The numbers after===
 
===The numbers after===
 
*The next odd number, 73, is a prime number.
 
*The next odd number, 73, is a prime number.

Revision as of 04:48, December 8, 2013

71 is a prime number from 1-100. 71 has 2 factors, 1 and 71. It is the twentieth prime number, and the twentieth prime number from 1-100.

Proofs

  • 1 can divide 71
  • 2 cannot
  • 3 cannot
  • 4 - 70 cannot
  • 71 can!

Relationship with other odd numbers

The numbers before

  • The previous odd number, 69, is not a prime number. It is divisible by 3.
  • The odd number previous to 69 is 67. 67 is a prime number.
    • 67 and 71 are four numbers apart; therefore, they are cousin primes.
  • The odd number previous to 67 is 65. 65 is not a prime number. It is divisible by 5.

The numbers after

  • The next odd number, 73, is a prime number.
    • There are no odd numbers between 71 and 73. As a result, they are twin primes.
  • 75, the odd number following 73, is not a prime number. It is divisible by 5.
  • 77, the odd number following 75, is also not a prime number. It is divisible by 7.
  • 79 is the next prime number after 73.
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