1001109991 has 32 divisors (see below), whose sum is σ = 1231718400. Its totient is φ = 794227200.

The previous prime is 1001109973. The next prime is 1001110007. The reversal of 1001109991 is 1999011001.

It is a cyclic number.

It is not a de Polignac number, because 1001109991 - 2⁹ = 1001109479 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 (1001109091) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2322546 + ... + 2322976.

It is an arithmetic number, because the mean of its divisors is an integer number (38491200).

Almost surely, 2^1001109991 is an apocalyptic number.

1001109991 is a deficient number, since it is larger than the sum of its proper divisors (230608409).

1001109991 is a wasteful number, since it uses less digits than its factorization.

1001109991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 735.

The product of its (nonzero) digits is 729, while the sum is 31.

The square root of 1001109991 is about 31640.3222328724. The cubic root of 1001109991 is about 1000.3698601866.

The spelling of 1001109991 in words is "one billion, one million, one hundred nine thousand, nine hundred ninety-one".