9991091 has 6 divisors (see below), whose sum is σ = 10982076. Its totient is φ = 9082700.

The previous prime is 9991067. The next prime is 9991123. The reversal of 9991091 is 1901999.

It is a happy number.

9991091 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 9991091 - 2⁶ = 9991027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9991691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 41165 + ... + 41406.

It is an arithmetic number, because the mean of its divisors is an integer number (1830346).

Almost surely, 2^9991091 is an apocalyptic number.

9991091 is a deficient number, since it is larger than the sum of its proper divisors (990985).

9991091 is a wasteful number, since it uses less digits than its factorization.

9991091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82593 (or 82582 counting only the distinct ones).

The product of its (nonzero) digits is 6561, while the sum is 38.

The square root of 9991091 is about 3160.8687097062. The cubic root of 9991091 is about 215.3794704651.

It can be divided in two parts, 99910 and 91, that added together give a palindrome (100001).

The spelling of 9991091 in words is "nine million, nine hundred ninety-one thousand, ninety-one".