22009 has 4 divisors (see below), whose sum is σ = 23716. Its totient is φ = 20304.

The previous prime is 22003. The next prime is 22013. The reversal of 22009 is 90022.

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 5625 + 16384 = 75^2 + 128^2 .

It is a cyclic number.

It is not a de Polignac number, because 22009 - 2⁵ = 21977 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1693 = 22009 / (2 + 2 + 0 + 0 + 9).

It is an Ulam number.

It is a Duffinian number.

22009 is a lucky number.

It is a plaindrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 22009.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 834 + ... + 859.

It is an arithmetic number, because the mean of its divisors is an integer number (5929).

2²²⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

22009 is a deficient number, since it is larger than the sum of its proper divisors (1707).

22009 is a wasteful number, since it uses less digits than its factorization.

22009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 22009 is about 148.3543056335. The cubic root of 22009 is about 28.0242137484.

Adding to 22009 its sum of digits (13), we get a palindrome (22022).

It can be divided in two parts, 2200 and 9, that added together give a square (2209 = 47²).

The spelling of 22009 in words is "twenty-two thousand, nine".