20404205 has 16 divisors (see below), whose sum is σ = 25633584. Its totient is φ = 15575040.

The previous prime is 20404187. The next prime is 20404213. The reversal of 20404205 is 50240402.

It can be written as a sum of positive squares in 8 ways, for example, as 885481 + 19518724 = 941^2 + 4418^2 .

It is not a de Polignac number, because 20404205 - 2¹⁰ = 20403181 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 (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8765 + ... + 10845.

It is an arithmetic number, because the mean of its divisors is an integer number (1602099).

Almost surely, 2^20404205 is an apocalyptic number.

It is an amenable number.

20404205 is a deficient number, since it is larger than the sum of its proper divisors (5229379).

20404205 is a wasteful number, since it uses less digits than its factorization.

20404205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2176.

The product of its (nonzero) digits is 320, while the sum is 17.

The square root of 20404205 is about 4517.1013935930. The cubic root of 20404205 is about 273.2582143695.

Adding to 20404205 its reverse (50240402), we get a palindrome (70644607).

The spelling of 20404205 in words is "twenty million, four hundred four thousand, two hundred five".