20641205 has 8 divisors (see below), whose sum is σ = 26674872. Its totient is φ = 15242688.

The previous prime is 20641141. The next prime is 20641207. The reversal of 20641205 is 50214602.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 192721 + 20448484 = 439^2 + 4522^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20641205 - 2⁶ = 20641141 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 (20641207) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 158714 + ... + 158843.

It is an arithmetic number, because the mean of its divisors is an integer number (3334359).

Almost surely, 2^20641205 is an apocalyptic number.

It is an amenable number.

20641205 is a deficient number, since it is larger than the sum of its proper divisors (6033667).

20641205 is a wasteful number, since it uses less digits than its factorization.

20641205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317575.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 20641205 is about 4543.2592926224. The cubic root of 20641205 is about 274.3121320842.

Adding to 20641205 its reverse (50214602), we get a palindrome (70855807).

The spelling of 20641205 in words is "twenty million, six hundred forty-one thousand, two hundred five".