10991009 has 4 divisors (see below), whose sum is σ = 11018820. Its totient is φ = 10963200.

The previous prime is 10991003. The next prime is 10991011. The reversal of 10991009 is 90019901.

10991009 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6027025 + 4963984 = 2455^2 + 2228^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10991009 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (10991003) 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 3 ways as a sum of consecutive naturals, for example, 13304 + ... + 14105.

It is an arithmetic number, because the mean of its divisors is an integer number (2754705).

Almost surely, 2^10991009 is an apocalyptic number.

It is an amenable number.

10991009 is a deficient number, since it is larger than the sum of its proper divisors (27811).

10991009 is an equidigital number, since it uses as much as digits as its factorization.

10991009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27810.

The product of its (nonzero) digits is 729, while the sum is 29.

The square root of 10991009 is about 3315.2690690199. The cubic root of 10991009 is about 222.3373991920.

The spelling of 10991009 in words is "ten million, nine hundred ninety-one thousand, nine".