209009 has 4 divisors (see below), whose sum is σ = 213504. Its totient is φ = 204516.

The previous prime is 208997. The next prime is 209021. The reversal of 209009 is 900902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 900902 = 2 ⋅450451.

It is an interprime number because it is at equal distance from previous prime (208997) and next prime (209021).

It is a cyclic number.

It is not a de Polignac number, because 209009 - 2⁴ = 208993 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 (209029) 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, 2177 + ... + 2270.

It is an arithmetic number, because the mean of its divisors is an integer number (53376).

2²⁰⁹⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

209009 is a deficient number, since it is larger than the sum of its proper divisors (4495).

209009 is an equidigital number, since it uses as much as digits as its factorization.

209009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4494.

The product of its (nonzero) digits is 162, while the sum is 20.

The square root of 209009 is about 457.1750211899. The cubic root of 209009 is about 59.3455732299.

The spelling of 209009 in words is "two hundred nine thousand, nine".