solution: we know that there are 25 prime numbers are between 1-100 and 168 prime numbers less than 1000. 100 x 100=10000(5 digits) 999 x 999=998001(6 digits) 1000 x 1000=1000000(7 digits) so our answer should be same as the number of prime numbers between 100 to 999. hence, 168-25=143. 143 prime numbers will be there less than 1000 whose square has 5 or 6 digits.
Smallest is 11 & Largest is 77.
73 satisfies your condition.
The smallest two-digit prime number whose digits themselves are prime is 23. Both 2 and 3 are prime numbers, and together they form the prime number 23.
11, 19, 41, 61, and 89
Two-digit prime numbers whose digits add up to 10 are:193773
Smallest is 11 & Largest is 77.
73 satisfies your condition.
The smallest two-digit prime number whose digits themselves are prime is 23. Both 2 and 3 are prime numbers, and together they form the prime number 23.
11, 19, 41, 61, and 89
Two-digit prime numbers whose digits add up to 10 are:193773
69
There are four pair of mirror primes.
Mirror primes are pairs of prime numbers whose digits are reversed. (13,31)(17,71)(37,73)(79,97)
The only two digit numbers whose digits add up to 17 are 89 and 98. Since 98 is an even number, 89 is prime.
It is composite, as are all whole numbers whose last digits are even.
23
numbers that do not end in 0, 2, 4, 5, 6 or 8; numbers whose digits do not total 3 or a multiple of 3