11009 has 4 divisors (see below), whose sum is σ = 11220. Its totient is φ = 10800.

The previous prime is 11003. The next prime is 11027. The reversal of 11009 is 90011.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 9409 + 1600 = 97^2 + 40^2 .

It is a cyclic number.

It is not a de Polignac number, because 11009 - 2⁴ = 10993 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (11003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47 + ... + 155.

It is an arithmetic number, because the mean of its divisors is an integer number (2805).

It is a Proth number, since it is equal to 43 ⋅ 2⁸ + 1 and 43 < 2⁸.

2¹¹⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

11009 is a deficient number, since it is larger than the sum of its proper divisors (211).

11009 is a wasteful number, since it uses less digits than its factorization.

11009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210.

The product of its (nonzero) digits is 9, while the sum is 11.

The square root of 11009 is about 104.9237818609. The cubic root of 11009 is about 22.2458646525.

The spelling of 11009 in words is "eleven thousand, nine".