118991 has 4 divisors (see below), whose sum is σ = 119712. Its totient is φ = 118272.

The previous prime is 118973. The next prime is 119027. The reversal of 118991 is 199811.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 118991 - 2⁶ = 118927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (118901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26 + ... + 488.

It is an arithmetic number, because the mean of its divisors is an integer number (29928).

2¹¹⁸⁹⁹¹ is an apocalyptic number.

118991 is a deficient number, since it is larger than the sum of its proper divisors (721).

118991 is an equidigital number, since it uses as much as digits as its factorization.

118991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 720.

The product of its digits is 648, while the sum is 29.

The square root of 118991 is about 344.9507211182. The cubic root of 118991 is about 49.1856073088.

The spelling of 118991 in words is "one hundred eighteen thousand, nine hundred ninety-one".