2165609 has 4 divisors (see below), whose sum is σ = 2216016. Its totient is φ = 2115204.

The previous prime is 2165599. The next prime is 2165617. The reversal of 2165609 is 9065612.

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.

It is a cyclic number.

It is not a de Polignac number, because 2165609 - 2⁴ = 2165593 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 (2165659) 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, 25139 + ... + 25224.

It is an arithmetic number, because the mean of its divisors is an integer number (554004).

2^2165609 is an apocalyptic number.

It is an amenable number.

2165609 is a deficient number, since it is larger than the sum of its proper divisors (50407).

2165609 is an equidigital number, since it uses as much as digits as its factorization.

2165609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50406.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 2165609 is about 1471.6008290294. The cubic root of 2165609 is about 129.3778756547.

The spelling of 2165609 in words is "two million, one hundred sixty-five thousand, six hundred nine".