20205505 has 4 divisors (see below), whose sum is σ = 24246612. Its totient is φ = 16164400.

The previous prime is 20205487. The next prime is 20205517. The reversal of 20205505 is 50550202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50550202 = 2 ⋅25275101.

It can be written as a sum of positive squares in 2 ways, for example, as 3370896 + 16834609 = 1836^2 + 4103^2 .

It is not a de Polignac number, because 20205505 - 2⁷ = 20205377 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2020546 + ... + 2020555.

It is an arithmetic number, because the mean of its divisors is an integer number (6061653).

Almost surely, 2^20205505 is an apocalyptic number.

It is an amenable number.

20205505 is a deficient number, since it is larger than the sum of its proper divisors (4041107).

20205505 is an equidigital number, since it uses as much as digits as its factorization.

20205505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4041106.

The product of its (nonzero) digits is 500, while the sum is 19.

The square root of 20205505 is about 4495.0533923414. The cubic root of 20205505 is about 272.3683060310.

Adding to 20205505 its reverse (50550202), we get a palindrome (70755707).

The spelling of 20205505 in words is "twenty million, two hundred five thousand, five hundred five".