107991 has 18 divisors (see below), whose sum is σ = 171288. Its totient is φ = 65520.

The previous prime is 107981. The next prime is 107999. The reversal of 107991 is 199701.

It is not a de Polignac number, because 107991 - 2⁶ = 107927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (107999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1486 + ... + 1556.

It is an arithmetic number, because the mean of its divisors is an integer number (9516).

2¹⁰⁷⁹⁹¹ is an apocalyptic number.

107991 is a deficient number, since it is larger than the sum of its proper divisors (63297).

107991 is a wasteful number, since it uses less digits than its factorization.

107991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 567, while the sum is 27.

The square root of 107991 is about 328.6198411539. The cubic root of 107991 is about 47.6207086881.

It can be divided in two parts, 1079 and 91, that multiplied together give a palindrome (98189).

The spelling of 107991 in words is "one hundred seven thousand, nine hundred ninety-one".