115811891 has 8 divisors (see below), whose sum is σ = 124813584. Its totient is φ = 106823520.

The previous prime is 115811879. The next prime is 115811903. The reversal of 115811891 is 198118511.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (115811879) and next prime (115811903).

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

It is a cyclic number.

It is not a de Polignac number, because 115811891 - 2²² = 111617587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (115811851) 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, 21800 + ... + 26586.

It is an arithmetic number, because the mean of its divisors is an integer number (15601698).

Almost surely, 2^115811891 is an apocalyptic number.

115811891 is a deficient number, since it is larger than the sum of its proper divisors (9001693).

115811891 is a wasteful number, since it uses less digits than its factorization.

115811891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6661.

The product of its digits is 2880, while the sum is 35.

The square root of 115811891 is about 10761.5933299860. The cubic root of 115811891 is about 487.4361306639.

The spelling of 115811891 in words is "one hundred fifteen million, eight hundred eleven thousand, eight hundred ninety-one".