Explain why 13233343563715 is a composite number. 

A composite number is a number which is not a prime number.A composite
number will be divisible by more than 2 numbers.
We shall use divisibility tests of prime numbers and prove that 13233343563715 is a composite number.
First, we check the divisibility by 2. The given number is not divisible by 2 because the given has 5 in the unit’s place.
We will check the divisibility by 3. A number will be divisible by 3 if the sum of its digits is divisible by 3. 

Sum of the given number is $1+3+2+3+3+3+4+3+5+6+3+7+1+5=49$. Adding the
digits of number 4 + 9 = 13. Since 13 is not divisible by 3, the given number is also not
divisible by 3.