Is 161 a prime number?

No, 161 is not a prime number. It is a composite number: 161 = 7 × 23.

Why 161 is not prime

161 has divisors other than 1 and itself. The smallest is 7: 161 ÷ 7 = 23.

Prime factorization: 161 = 7 × 23.

Quick facts about 161

Is it prime? Nearby numbers

NumberPrime?
157Yes
158No, 2 × 79
159No, 3 × 53
160No, 2 × 2 × 2 × 2 × 2 × 5
162No, 2 × 3 × 3 × 3 × 3
163Yes
164No, 2 × 2 × 41
165No, 3 × 5 × 11

More about 161: factors of 161 · square root of 161 · 161 in binary.

Another number? Use the prime number checker for any value, or see the list of prime numbers.