Prime numbers

A prime number (often simply called a prime) is a natural number which can only be divided exactly by 1 and itself. An infinite number of prime numbers exists.

Primes to 250

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	163	167	173	179
181	191	193	197	199	211	223	227	229	233
239	241

The number two is the only even prime, all the others are odd. Two is a prime number because it can only be made by multiplying 2 by 1. Four is not a prime number as it can be made by multiplying 2 by 2.

The number 1 is a special case, and is not considered a prime number.

Did you know?

Prime numbers form are an essential part of internet security due to the principle that multiplication of large integers is easy, but finding the prime factors of the product is much harder.

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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	163	167	173	179
181	191	193	197	199	211	223	227	229	233
239	241

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	163	167	173	179
181	191	193	197	199	211	223	227	229	233
239	241

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	163	167	173	179
181	191	193	197	199	211	223	227	229	233
239	241