118381891 has 4 divisors (see below), whose sum is σ = 118853784. Its totient is φ = 117910000.

The previous prime is 118381889. The next prime is 118381927. The reversal of 118381891 is 198183811.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198183811 = 7 ⋅28311973.

It is a cyclic number.

It is not a de Polignac number, because 118381891 - 2¹ = 118381889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (118381811) 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, 235570 + ... + 236071.

It is an arithmetic number, because the mean of its divisors is an integer number (29713446).

Almost surely, 2^118381891 is an apocalyptic number.

118381891 is a deficient number, since it is larger than the sum of its proper divisors (471893).

118381891 is an equidigital number, since it uses as much as digits as its factorization.

118381891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471892.

The product of its digits is 13824, while the sum is 40.

The square root of 118381891 is about 10880.3442500686. The cubic root of 118381891 is about 491.0153747106.

The spelling of 118381891 in words is "one hundred eighteen million, three hundred eighty-one thousand, eight hundred ninety-one".