20839205 has 4 divisors (see below), whose sum is σ = 25007052. Its totient is φ = 16671360.

The previous prime is 20839201. The next prime is 20839243. The reversal of 20839205 is 50293802.

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 16008001 + 4831204 = 4001^2 + 2198^2 .

It is not a de Polignac number, because 20839205 - 2² = 20839201 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 (20839201) 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, 2083916 + ... + 2083925.

It is an arithmetic number, because the mean of its divisors is an integer number (6251763).

Almost surely, 2^20839205 is an apocalyptic number.

It is an amenable number.

20839205 is a deficient number, since it is larger than the sum of its proper divisors (4167847).

20839205 is an equidigital number, since it uses as much as digits as its factorization.

20839205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4167846.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 20839205 is about 4564.9978094190. The cubic root of 20839205 is about 275.1864520679.

The spelling of 20839205 in words is "twenty million, eight hundred thirty-nine thousand, two hundred five".