First 20 Prime Numbers

The first 20 prime numbers. Primes are divisible only by 1 and themselves — they are the building blocks of all integers.

2 is the only even prime — every other even number divides by 2. The widest gap between consecutive neighbors in this list is 6: primes wander further apart as numbers grow, yet never run out — Euclid proved the supply is endless. The list stays tight as well: all 20 of these primes fit inside the range 2 through 71, where they make up about 28.2% of all integers — prime density thins slowly as numbers grow.

The first 20 prime numbers, in order from 2
#	Prime
1	2
2	3
3	5
4	7
5	11
6	13
7	17
8	19
9	23
10	29
11	31
12	37
13	41
14	43
15	47
16	53
17	59
18	61
19	67
20	71

Frequently asked questions

What are the first 20 prime numbers?

The first 20 primes are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29….

What is the 20th prime number?

71 is the 20th prime number.

Why is 1 not a prime number?

A prime must have exactly two distinct factors: 1 and itself. The number 1 has only one factor, so it is not prime (and not composite either).

Related calculators

Prime Checker Prime Factorization All tables

#	Prime
1	2
2	3
3	5
4	7
5	11
6	13
7	17
8	19
9	23
10	29
11	31
12	37
13	41
14	43
15	47
16	53
17	59
18	61
19	67
20	71

#	Prime
1	2
2	3
3	5
4	7
5	11
6	13
7	17
8	19
9	23
10	29
11	31
12	37
13	41
14	43
15	47
16	53
17	59
18	61
19	67
20	71