111781891 has 8 divisors (see below), whose sum is σ = 120508640. Its totient is φ = 103073472.

The previous prime is 111781861. The next prime is 111781991. The reversal of 111781891 is 198187111.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111781891 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 111781891.

It is not an unprimeable number, because it can be changed into a prime (111781861) 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 7 ways as a sum of consecutive naturals, for example, 9775 + ... + 17863.

It is an arithmetic number, because the mean of its divisors is an integer number (15063580).

Almost surely, 2^111781891 is an apocalyptic number.

111781891 is a deficient number, since it is larger than the sum of its proper divisors (8726749).

111781891 is a wasteful number, since it uses less digits than its factorization.

111781891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9165.

The product of its digits is 4032, while the sum is 37.

The square root of 111781891 is about 10572.6955408732. The cubic root of 111781891 is about 481.7153484771.

The spelling of 111781891 in words is "one hundred eleven million, seven hundred eighty-one thousand, eight hundred ninety-one".