2009839805 has 4 divisors (see below), whose sum is σ = 2411807772. Its totient is φ = 1607871840.

The previous prime is 2009839801. The next prime is 2009839829. The reversal of 2009839805 is 5089389002.

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 765020281 + 1244819524 = 27659^2 + 35282^2 .

It is not a de Polignac number, because 2009839805 - 2² = 2009839801 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2009839801) 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, 200983976 + ... + 200983985.

It is an arithmetic number, because the mean of its divisors is an integer number (602951943).

Almost surely, 2^2009839805 is an apocalyptic number.

It is an amenable number.

2009839805 is a deficient number, since it is larger than the sum of its proper divisors (401967967).

2009839805 is an equidigital number, since it uses as much as digits as its factorization.

2009839805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401967966.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 2009839805 is about 44831.2369336381. The cubic root of 2009839805 is about 1261.9839001515.

The spelling of 2009839805 in words is "two billion, nine million, eight hundred thirty-nine thousand, eight hundred five".