8991391166 has 16 divisors (see below), whose sum is σ = 14391416400. Its totient is φ = 4200735168.

The previous prime is 8991391141. The next prime is 8991391207. The reversal of 8991391166 is 6611931998.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1617881 + ... + 1623428.

It is an arithmetic number, because the mean of its divisors is an integer number (899463525).

Almost surely, 2^8991391166 is an apocalyptic number.

8991391166 is a deficient number, since it is larger than the sum of its proper divisors (5400025234).

8991391166 is a wasteful number, since it uses less digits than its factorization.

8991391166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3241403.

The product of its digits is 629856, while the sum is 53.

The square root of 8991391166 is about 94822.9464106658. The cubic root of 8991391166 is about 2079.4203856824.

The spelling of 8991391166 in words is "eight billion, nine hundred ninety-one million, three hundred ninety-one thousand, one hundred sixty-six".