20805039 has 8 divisors (see below), whose sum is σ = 30822320. Its totient is φ = 13870008.

The previous prime is 20805017. The next prime is 20805047. The reversal of 20805039 is 93050802.

It is not a de Polignac number, because 20805039 - 2⁷ = 20804911 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 770557 = 20805039 / (2 + 0 + 8 + 0 + 5 + 0 + 3 + 9).

It is a Duffinian number.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20805049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 385252 + ... + 385305.

It is an arithmetic number, because the mean of its divisors is an integer number (3852790).

Almost surely, 2^20805039 is an apocalyptic number.

20805039 is a deficient number, since it is larger than the sum of its proper divisors (10017281).

20805039 is an equidigital number, since it uses as much as digits as its factorization.

20805039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 770566 (or 770560 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 20805039 is about 4561.2541038622. The cubic root of 20805039 is about 275.0359798653.

The spelling of 20805039 in words is "twenty million, eight hundred five thousand, thirty-nine".