20011205 has 16 divisors (see below), whose sum is σ = 24513840. Its totient is φ = 15679488.

The previous prime is 20011177. The next prime is 20011249. The reversal of 20011205 is 50211002.

It can be written as a sum of positive squares in 8 ways, for example, as 5134756 + 14876449 = 2266^2 + 3857^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20011205 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 85769 + ... + 86001.

It is an arithmetic number, because the mean of its divisors is an integer number (1532115).

Almost surely, 2^20011205 is an apocalyptic number.

It is an amenable number.

20011205 is a deficient number, since it is larger than the sum of its proper divisors (4502635).

20011205 is a wasteful number, since it uses less digits than its factorization.

20011205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 20011205 is about 4473.3885366688. The cubic root of 20011205 is about 271.4924439447.

Adding to 20011205 its reverse (50211002), we get a palindrome (70222207).

The spelling of 20011205 in words is "twenty million, eleven thousand, two hundred five".