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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.

## Proofs

• — 991 can be divided by 1.
• — 991 cannot be divided by 2-990.
• — 991 can be divided by 991.

## Relationship with other odd numbers

### The numbers before

• 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 after

• 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.

## Trivia

• 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.
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