Palindromic prime facts for kids
A palindromic prime number is a special kind of prime number. It's a number that reads the same forwards and backwards. Think of it like a word that's the same forwards and backwards, like "madam" or "racecar." For numbers, this means the digits are symmetrical.
For example, the number 131 is a palindromic prime. If you read it from left to right, it's 1-3-1. If you read it from right to left, it's also 1-3-1. Plus, 131 is a prime number, meaning it can only be divided evenly by 1 and itself.
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What are Palindromic Prime Numbers?
A prime number is a whole number greater than 1 that has no positive divisors other than 1 and itself. For example, 7 is a prime number because you can only divide it by 1 and 7. The number 6 is not prime because you can divide it by 1, 2, 3, and 6.
A palindrome is something that reads the same forwards and backwards. This can be a word, a phrase, or a number. When a prime number is also a palindrome, we call it a palindromic prime.
Examples of Palindromic Primes
Here are some examples of palindromic prime numbers:
- 2
- 3
- 5
- 7
- 11
- 101
- 131
- 151
- 181
- 191
- 313
- 353
- 373
- 383
- 727
- 757
- 787
- 797
- 919
- 929
- 10301
- 10501
- 10601
- 11311
- 11411
- 12421
- 12721
- 12821
- 13331
- 13831
- 13931
- 14341
- 14741
- 15451
- 15551
- 16061
- 16361
- 16561
- 16661
- 17471
- 17971
- 18181
- 18481
- 19391
- 19891
- 19991
Special Palindromic Primes
The number 2 is unique among palindromic primes. It is the only one that is an even number. All other palindromic primes are odd numbers. This is because any even number greater than 2 can be divided by 2, meaning it wouldn't be a prime number.
The number 11 is also very special. It is the only palindromic prime that has an even number of digits. For example, 11 has two digits, which is an even number. Any other palindromic number with an even number of digits (like 1221 or 123321) can always be divided by 11. If a number can be divided by 11, it means it's not a prime number (unless it's 11 itself!).
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