20803809 has 16 divisors (see below), whose sum is σ = 29960000. Its totient is φ = 12764736.

The previous prime is 20803807. The next prime is 20803819. The reversal of 20803809 is 90830802.

It is not a de Polignac number, because 20803809 - 2¹ = 20803807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20803807) 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 15 ways as a sum of consecutive naturals, for example, 18927 + ... + 19995.

It is an arithmetic number, because the mean of its divisors is an integer number (1872500).

Almost surely, 2^20803809 is an apocalyptic number.

It is an amenable number.

20803809 is a deficient number, since it is larger than the sum of its proper divisors (9156191).

20803809 is a wasteful number, since it uses less digits than its factorization.

20803809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1584.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 20803809 is about 4561.1192705300. The cubic root of 20803809 is about 275.0305596893.

It can be divided in two parts, 20803 and 809, that added together give a palindrome (21612).

The spelling of 20803809 in words is "twenty million, eight hundred three thousand, eight hundred nine".