Prime Numbers Math Example 4

Follow the full solution, then compare it with the other examples linked below.

Example 4

easy
Is 5151 prime or composite?

Solution

  1. 1
    Use the divisibility rule for 3: 5+1=65 + 1 = 6, and 6 is divisible by 3, so 51 is divisible by 3.
  2. 2
    Since 51=3×1751 = 3 \times 17, it has factors other than 1 and itself, so it is composite.

Answer

Composite\text{Composite}
A prime number has exactly two positive factors. Once you find any nontrivial factor, the number must be composite.

About Prime Numbers

Integers greater than 1 whose only positive divisors are 1 and themselves—they cannot be factored further.

Learn more about Prime Numbers →

More Prime Numbers Examples

Example 1 easy

Find the prime factorization of [formula].

Example 2 medium

Determine whether [formula] is prime.

Example 3 easy

List all prime numbers between 20 and 40.

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