20503205 has 4 divisors (see below), whose sum is σ = 24603852. Its totient is φ = 16402560.

The previous prime is 20503193. The next prime is 20503213. The reversal of 20503205 is 50230502.

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 16370116 + 4133089 = 4046^2 + 2033^2 .

It is not a de Polignac number, because 20503205 - 2⁶ = 20503141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2050316 + ... + 2050325.

It is an arithmetic number, because the mean of its divisors is an integer number (6150963).

Almost surely, 2^20503205 is an apocalyptic number.

It is an amenable number.

20503205 is a deficient number, since it is larger than the sum of its proper divisors (4100647).

20503205 is an equidigital number, since it uses as much as digits as its factorization.

20503205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4100646.

The product of its (nonzero) digits is 300, while the sum is 17.

The square root of 20503205 is about 4528.0464882773. The cubic root of 20503205 is about 273.6994457774.

Adding to 20503205 its reverse (50230502), we get a palindrome (70733707).

The spelling of 20503205 in words is "twenty million, five hundred three thousand, two hundred five".