Charts & references · 3 min read
Prime Numbers Up to 200: Full List and How to Find Them
The list
| Range | Primes |
|---|---|
| 1–50 | 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47 |
| 51–100 | 53, 59, 61, 67, 71, 73, 79, 83, 89, 97 |
| 101–150 | 101, 103, 107, 109, 113, 127, 131, 137, 139, 149 |
| 151–200 | 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199 |
Count per block: 15, 10, 10, 11.
The Sieve of Eratosthenes
List 2 to 200. Keep 2 and cross out its multiples. Move to the next uncrossed number, 3, keep it and cross out its multiples. Repeat. You only need to sieve with primes up to √200 ≈ 14, i.e. 2, 3, 5, 7, 11 and 13; everything left is prime.
Quick primality test
Test divisibility by primes up to the square root. For 191: √191 ≈ 13.8, and none of 2, 3, 5, 7, 11, 13 divide it, so it is prime. Confirm with the prime factorization calculator: 191 is prime.
187 looks prime, but is it?
- Divisors: 4
- Sum of divisors: 216
Step-by-step working 3 steps
- 1Divide by the smallest prime that fits, again and again
187 ÷ 11 = 17 17 ÷ 17 = 1
Stop when the quotient reaches 1.
- 2Collect the primes
187 = 11 × 17
- 3Count the divisors
(2 × 2) = 4 divisors
Add 1 to each exponent and multiply.
Facts worth knowing
- 2 is the only even prime.
- 1 is not prime.
- Every whole number above 1 has exactly one prime factorization.
- There are infinitely many primes.
See also prime numbers explained and how primes protect the internet.
Frequently asked questions
How many primes are there under 100?
25.
Is 1 a prime number?
No. A prime has exactly two distinct divisors, and 1 has only one.
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