9115991 has 8 divisors (see below), whose sum is σ = 9648000. Its totient is φ = 8589240.

The previous prime is 9115943. The next prime is 9115993. The reversal of 9115991 is 1995119.

9115991 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

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 9115991 - 2¹⁰ = 9114967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9115993) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2576 + ... + 4986.

It is an arithmetic number, because the mean of its divisors is an integer number (1206000).

Almost surely, 2^9115991 is an apocalyptic number.

9115991 is a deficient number, since it is larger than the sum of its proper divisors (532009).

9115991 is a wasteful number, since it uses less digits than its factorization.

9115991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2629.

The product of its digits is 3645, while the sum is 35.

The square root of 9115991 is about 3019.2699448708. The cubic root of 9115991 is about 208.8981670070.

The spelling of 9115991 in words is "nine million, one hundred fifteen thousand, nine hundred ninety-one".