20205305 has 16 divisors (see below), whose sum is σ = 24791184. Its totient is φ = 15805440.

The previous prime is 20205301. The next prime is 20205307. The reversal of 20205305 is 50350202.

It can be written as a sum of positive squares in 8 ways, for example, as 2699449 + 17505856 = 1643^2 + 4184^2 .

It is not a de Polignac number, because 20205305 - 2² = 20205301 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20205301) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71765 + ... + 72045.

It is an arithmetic number, because the mean of its divisors is an integer number (1549449).

Almost surely, 2^20205305 is an apocalyptic number.

It is an amenable number.

20205305 is a deficient number, since it is larger than the sum of its proper divisors (4585879).

20205305 is a wasteful number, since it uses less digits than its factorization.

20205305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 556.

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

The square root of 20205305 is about 4495.0311456096. The cubic root of 20205305 is about 272.3674073676.

Adding to 20205305 its reverse (50350202), we get a palindrome (70555507).

The spelling of 20205305 in words is "twenty million, two hundred five thousand, three hundred five".