13, 23, 43, 53, 73, 83
2, 3, 5, and 7 are the only one-digit prime numbers.
non-prime no.
24 of them.
0 Look at the product of the first 3 prime numbers: 2 x 3 x 5 = 30. Any number multiplied by 30 will have a 0 in the units digit. So, no matter how many prime numbers you are multiplying, if once you have a number ending in 0, all of the rest will end in 0.
71,73,79
No. Like all numbers ending in the digit 4, it is even.
All the two digit prime numbers that can be reversed are 11, 13 and 31, 17 and 71, 37 and 73, and 79 and 97.
For a 2-digit prime number (which are all odd) to be the sum of two prime numbers, one of the prime numbers will have to be 2. That means the difference between the sum and the other addend will have to be 2. Prime numbers that differ by 2 are called twin primes. There are six pairs of 2-digit twin primes. Your numbers are 13, 19, 31, 43, 61 and 73.
Only one positive prime number has a 5 in the ones digit. That prime number is 5. All other numbers with a 5 in the ones digit are composite because they will be divisible by 5.
Numbers that are not prime are numbers that are divisible by integers other than one and itself. Since there are a boatload of these numbers, I will try to keep it brief:All integers with the last digit 2, 4, 6, 8, or 0 (besides 2 and 0 themselves) are not prime. (Numbers that are not prime are composite. Numbers ending in 2, 4, 6, 8, or 0 are always divisible by at least the number 2, hence they are not prime.)All integers ending with 5 (besides 5 itself) are not prime (these numbers are always divisible by at least the number 5).Everything else varies, though. For example, with digits ending with 3, 33 is not prime (divisible by 3 and 11), but 13 is prime. With 7, 17 is prime, but 77 is not (divisible by 11 and 7). Also, two-digit integers with identical tens and ones-place digits are not prime (with the exception of 11); these are all divisible by 11.That's the general rule of prime vs. not prime. As you can see, it's too lengthy and excruciatingly painful to list ALL of the composites, because they are abundant.
No. All whole numbers ending in zero are composite.