2805209 has 4 divisors (see below), whose sum is σ = 3060240. Its totient is φ = 2550180.

The previous prime is 2805203. The next prime is 2805227. The reversal of 2805209 is 9025082.

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 2805209 - 2⁴ = 2805193 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 (2805203) 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, 127499 + ... + 127520.

It is an arithmetic number, because the mean of its divisors is an integer number (765060).

2^2805209 is an apocalyptic number.

It is an amenable number.

2805209 is a deficient number, since it is larger than the sum of its proper divisors (255031).

2805209 is a wasteful number, since it uses less digits than its factorization.

2805209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255030.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 2805209 is about 1674.8758162921. The cubic root of 2805209 is about 141.0333237804.

The spelling of 2805209 in words is "two million, eight hundred five thousand, two hundred nine".