A prime number is a whole number greater than 1 whose only factors are 1 and itself. A factor is a whole numbers that can be divided evenly into another number. The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23 and 29.
So, what is the prime number of 21?
When a number has more than two factors it is called a composite number. Here are the first few prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, etc.
What are all of the multiples of 21?
Answer : 21,42,63,84,105,126,147,168,189,210,231,252,273,294,315,336,357,378,399,420,441,462,483,504,525,546,567,588,609,630,651,672,693,714,735,756,777,798,819,840,861,882,903,924,945,966,987,1008,1029, Related Links : What are the factors of 21?
What is the prime factors of 20?
20 is a composite number. 20 = 1 x 20, 2 x 10, or 4 x 5. Factors of 20: 1, 2, 4, 5, 10, 20. Prime factorization: 20 = 2 x 2 x 5, which can also be written 20 = 2² x 5.