20203809 has 4 divisors (see below), whose sum is σ = 26938416. Its totient is φ = 13469204.

The previous prime is 20203793. The next prime is 20203811. The reversal of 20203809 is 90830202.

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 20203809 - 2⁴ = 20203793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20203849) 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, 3367299 + ... + 3367304.

It is an arithmetic number, because the mean of its divisors is an integer number (6734604).

Almost surely, 2^20203809 is an apocalyptic number.

It is an amenable number.

20203809 is a deficient number, since it is larger than the sum of its proper divisors (6734607).

20203809 is an equidigital number, since it uses as much as digits as its factorization.

20203809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6734606.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 20203809 is about 4494.8647365633. The cubic root of 20203809 is about 272.3606851776.

It can be divided in two parts, 20203 and 809, that added together give a palindrome (21012).

The spelling of 20203809 in words is "twenty million, two hundred three thousand, eight hundred nine".