118643991 has 8 divisors (see below), whose sum is σ = 158242560. Its totient is φ = 79070712.

The previous prime is 118643983. The next prime is 118644007. The reversal of 118643991 is 199346811.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 118643991 - 2³ = 118643983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (118643891) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13570 + ... + 20528.

It is an arithmetic number, because the mean of its divisors is an integer number (19780320).

Almost surely, 2^118643991 is an apocalyptic number.

118643991 is a deficient number, since it is larger than the sum of its proper divisors (39598569).

118643991 is an equidigital number, since it uses as much as digits as its factorization.

118643991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12645.

The product of its digits is 46656, while the sum is 42.

The square root of 118643991 is about 10892.3822463224. The cubic root of 118643991 is about 491.3774803991.

The spelling of 118643991 in words is "one hundred eighteen million, six hundred forty-three thousand, nine hundred ninety-one".