115991121 has 8 divisors (see below), whose sum is σ = 154764000. Its totient is φ = 77272832.

The previous prime is 115991111. The next prime is 115991123. The reversal of 115991121 is 121199511.

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 115991121 - 2¹³ = 115982929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (115991123) 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, 8400 + ... + 17393.

It is an arithmetic number, because the mean of its divisors is an integer number (19345500).

Almost surely, 2^115991121 is an apocalyptic number.

It is an amenable number.

115991121 is a deficient number, since it is larger than the sum of its proper divisors (38772879).

115991121 is a wasteful number, since it uses less digits than its factorization.

115991121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27295.

The product of its digits is 810, while the sum is 30.

The square root of 115991121 is about 10769.9174091541. The cubic root of 115991121 is about 487.6874524353.

It can be divided in two parts, 11599 and 1121, that added together give a triangular number (12720 = T₁₅₉).

The spelling of 115991121 in words is "one hundred fifteen million, nine hundred ninety-one thousand, one hundred twenty-one".