9090099991 has 16 divisors (see below), whose sum is σ = 10521116928. Its totient is φ = 7692321600.

The previous prime is 9090099943. The next prime is 9090100069. The reversal of 9090099991 is 1999900909.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 9090099991 - 2²⁷ = 8955882263 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9090091991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 995356 + ... + 1004446.

It is an arithmetic number, because the mean of its divisors is an integer number (657569808).

Almost surely, 2^9090099991 is an apocalyptic number.

9090099991 is a deficient number, since it is larger than the sum of its proper divisors (1431016937).

9090099991 is a wasteful number, since it uses less digits than its factorization.

9090099991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10902.

The product of its (nonzero) digits is 531441, while the sum is 55.

The square root of 9090099991 is about 95342.0158744297. The cubic root of 9090099991 is about 2087.0021036649.

The spelling of 9090099991 in words is "nine billion, ninety million, ninety-nine thousand, nine hundred ninety-one".