Prime Numbers

1 x 3 x 13

settalite

210 = 21x10 = (3x7)(2x5) = 2x3x5x7.

The following sets of factors all fit the conditions of the question:

2,3,5,7; 5,6,7; 2,7,15; 2,3,35; 3,10,7; 2,5,21 and 3,5,14.

43 is already prime.

107 is, itself, a prime number.

47 - 2 = 45

No because it has more than two factors

42 = 1 x 2 x 3 x 7

Well, look. This number is huge but that si not a problem. Notice how it ends in 4? well that means it can be divided by 2! so it is not a prime number.

The only such number is zero.

It is 67

2 x 2 x 2 x 45

2 x 2 x 3 x 30

2 x 2 x 5 x 18

2 x 3 x 3 x 20

2 x 3 x 5 x 12

3 x 3 x 5 x 8

2 x 2 x 2 x 3 x 15

2 x 2 x 3 x 3 x 10

2 x 2 x 3 x 5 x 6

2 x 3 x 3 x 4 x 5

2 x 2 x 2 x 5 x 9

2 x 2 x 2 x 3 x 3 x 5

2

no

3 and 5.

3 and 5.

3 and 5.

3 and 5.

2/7-5/19

675,511 is a prime number.

A prime factor = prime number which can be divided into the given number with no remainder Prime factors of 150 are: 2, 3, and 5.

6

1,069

10 and 20 are composite numbers, not prime numbers.

The prime factorization of 10 is 2 x 5.

The prime factorization of 20 is 2 x 2 x 5.

2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199 211 223 227 229 233 239 241 251 257 263 269 271 277 281 283 293 307 311 313 317 331 337 347 349 353 359 367 373 379 383 389 397 401 409 419 421 431 433 439 443 449 457 461 463 467 479 487 491 499.

1,100 = 22 × 52 × 11

No, 154 is not a prime number.

Any number that ends in 0, 2, 4, 6 or 8 is an even number, and no even number (apart from 2) is prime.

Factors of 154 include 2 x 77, 11 x 14 and 7 x 22.