Question

Explain why (7 × 11 × 13 + 2 × 11) is not a prime number.

Answer 1

Simplify the given expression

7 × 11 × 13 + 2 × 11 = 1001 + 22

= 1023

Prime factorisation of 1023 = 3 × 11 × 31

Thus, 1023 is divisible by 3, 11 and 31.

Since, a prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Therefore, 1023 is not a prime number as it has other divisors other than 1 and itself.

Hence, (7 × 11 × 13+ 2 × 11) is not a prime number.