2, 3, 5, and 7 are the only one-digit prime numbers.
24 of them.
71,73,79
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.
2, 3, 5, and 7 are the only one-digit prime numbers.
non-prime no.
24 of them.
71,73,79
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.
The ones digit in the product from multiplying the 305 prime numbers less than 2012 is 0 because the ones digit becomes 0 after 2 and 5 have been multiplied and remains unchanged after more prime numbers are multiplied.
The smallest prime number in which all of the digits are also prime is 2.The smallest multi-digit prime number in which all of the digits are also prime is 23.
No two digit prime number exists that is a multiple of 7. All two digit numbers that are multiples of 7 are compositenumbers.
11, 19, 41, 61, and 89
13, 23, 43, 53, 73, 83