The possibilities for a digit in the ones place of a prime number greater than 5 are 1, 3, 7, and 9.
If a 0, 2, 4, 6, or 8 is in the ones place, the number is divisible by 2, so it would not be prime. If a 5 is in the ones place, the number is divisible by 5, so it would not be prime.
No, 11 is the only palindromic prime with an even number of digits.
The largest three digit prime number whose digits are all primes is 773.
The largest 3 digit number whose digits are all primes is 777. The largest 3 digit number with different prime digits is 753.
Composite
Given an arbitrary odd natural number greater than five, x, let y = x - 3, then y is an even number greater than 2. By assumption we have that y is the sum of two primes, say y1 and y2, but then x = y1 + y2 + 3 (which is the sum of three primes).
No, 11 is the only palindromic prime with an even number of digits.
The longest string of consecutive numbers that are primes is two digits long, consisting of 2 and 3 only. There are no other consecutive numbers that are primes because no even numbers greater than 2 are primes.
472.
The largest three digit prime number whose digits are all primes is 773.
The largest 3 digit number whose digits are all primes is 777. The largest 3 digit number with different prime digits is 753.
The answer is 418. You are copying a MathCounts problem.
Three of them.
373
How about: 773
Composite
18713, 18719, 18731, 18743, 18749 18731 is the center of the 5 primes. Notice that the distance from it to each on the the left and right is the same. Now do you see what a symmetrical primes is?
A boatloadThere are in infinite number or primes, and they are still being discovered. The people who discover the prime that has more than 10 million digits will win $100,000. I'm pretty sure they're getting close, something like 9.8 million digits.