A Prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite. yes, there are 8 digit prime numbers.
To find the total number of 8-digit numbers, we consider the range of 8-digit numbers, which starts from 10,000,000 and ends at 99,999,999. The first digit (most significant) can be any digit from 1 to 9 (9 options), while the remaining 7 digits can each be any digit from 0 to 9 (10 options each). Thus, the total number of 8-digit numbers is calculated as (9 \times 10^7), which equals 90,000,000.
8
A prime number is evenly divisible only by itself and one. Any three digit number ending in 0, 2, 4, 6, or 8 is evenly divisible by 2 - so not a prime Any three digit number ending in 5 is divisible by 5, so not a prime number. The only even prime number is 2. The only prime number that ends in 5 is 5.
17 is a prime number. 8 and 12 are not prime numbers.
8, 11, and 20.
The ratio of the number of one-digit prime numbers to the number of one-digit composite numbers is one to one. The one-digit prime numbers are 2, 3, 5, and 7. The one-digit composite numbers are 4, 6, 8, and 9. Therefor, the ratio is 4:4, which simplifies to 1:1.
17
Using prime factorization, there are 2 three digit numbers with 9 factors: 512 and 768. There are no three digit numbers with 10 or more prime factors. 512=2^9 and 768=3*2^8
The smallest three-digit number divisible by the first three prime numbers (2, 3, and 5) and the first three composite numbers (4, 6, and 8) is 120.
That's close to five million numbers. I'm not printing out five million numbers. There are plenty of online resources where that information can be found.
3
There is only one even prime number (2). There are no 8-digit even primes.
8
17, 53 and 71 all qualify.
A prime number is evenly divisible only by itself and one. Any three digit number ending in 0, 2, 4, 6, or 8 is evenly divisible by 2 - so not a prime Any three digit number ending in 5 is divisible by 5, so not a prime number. The only even prime number is 2. The only prime number that ends in 5 is 5.
There are eight prime numbers under 20.
6, if you don't repeat any numbers.