20505055 has 4 divisors (see below), whose sum is σ = 24606072. Its totient is φ = 16404040.

The previous prime is 20505049. The next prime is 20505083. The reversal of 20505055 is 55050502.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20505055 - 2⁹ = 20504543 is a prime.

It is a Duffinian number.

It is a congruent 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, 2050501 + ... + 2050510.

It is an arithmetic number, because the mean of its divisors is an integer number (6151518).

Almost surely, 2^20505055 is an apocalyptic number.

20505055 is a deficient number, since it is larger than the sum of its proper divisors (4101017).

20505055 is an equidigital number, since it uses as much as digits as its factorization.

20505055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4101016.

The product of its (nonzero) digits is 1250, while the sum is 22.

The square root of 20505055 is about 4528.2507660243. The cubic root of 20505055 is about 273.7076774782.

Adding to 20505055 its reverse (55050502), we get a palindrome (75555557).

The spelling of 20505055 in words is "twenty million, five hundred five thousand, fifty-five".