991 is a prime number from 901-1000. 991 has 2 factors, 1 and 991. It is the 167th prime number, and the thirteenth prime number from 901-1000.

## ProofsEdit

## Relationship with other odd numbersEdit

### The numbers beforeEdit

- The previous prime number is 983, 8 numbers away.
- 987 is the product of 3, 7, and 47.
- 989 is the product of 23 and 43.

### The numbers afterEdit

- The next prime number is 997.
- 991 and 997 are sexy primes.

- 1,009 is the next prime number after 997. The gap between the two numbers is 12.
- 1,001 is divisible by 7, 1,003 by 17, and 1,007 by 19.

## TriviaEdit

- 991, 99991, and 9999991 are all prime.
- This number, 331 and 661 are all prime. Note that the product of these three primes is a Carmichael Number.
- The largest three-digit permutable prime.
- 991^2 = 982081 and 982 + 0 + 8 + 1 = 991.
- Florida angler Allen Ogle caught a 991-pound Hammerhead Shark on May 30, 1982.