2039809 has 4 divisors (see below), whose sum is σ = 2048004. Its totient is φ = 2031616.

The previous prime is 2039797. The next prime is 2039819. The reversal of 2039809 is 9089302.

It is a happy number.

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 2016400 + 23409 = 1420^2 + 153^2 .

It is a cyclic number.

It is not a de Polignac number, because 2039809 - 2⁵ = 2039777 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 (2039819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3712 + ... + 4225.

It is an arithmetic number, because the mean of its divisors is an integer number (512001).

It is a Proth number, since it is equal to 249 ⋅ 2¹³ + 1 and 249 < 2¹³.

2^2039809 is an apocalyptic number.

It is an amenable number.

2039809 is a deficient number, since it is larger than the sum of its proper divisors (8195).

2039809 is an equidigital number, since it uses as much as digits as its factorization.

2039809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8194.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 2039809 is about 1428.2188207694. The cubic root of 2039809 is about 126.8225558364.

The spelling of 2039809 in words is "two million, thirty-nine thousand, eight hundred nine".