Investigate the Number 31: Is it a Prime?

The number 31

To determine the divisibility of 31, we apply the rules for divisibility by 2, 4, and 10:

• Divisibility by 2: A number is divisible by 2 if its last digit is even. The last digit of 31 is 1, which is not even. Therefore, 31 is not divisible by 2.
• Divisibility by 4: A number is divisible by 4 if the number formed by its last two digits is divisible by 4. The last two digits of 31 are 31, and 31 divided by 4 gives a remainder. Therefore, 31 is not divisible by 4.
• Divisibility by 10: A number is divisible by 10 if its last digit is 0. The last digit of 31 is 1, not 0. Therefore, 31 is not divisible by 10.

Considering these results, 31 is not divisible by any of the options provided. Therefore, the correct choice is:

Is not divisible by any of the options