21033520205 has 4 divisors (see below), whose sum is σ = 25240224252. Its totient is φ = 16826816160.

The previous prime is 21033520153. The next prime is 21033520223. The reversal of 21033520205 is 50202533012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8051652361 + 12981867844 = 89731^2 + 113938^2 .

It is not a de Polignac number, because 21033520205 - 2¹⁰ = 21033519181 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, 2103352016 + ... + 2103352025.

It is an arithmetic number, because the mean of its divisors is an integer number (6310056063).

Almost surely, 2^21033520205 is an apocalyptic number.

It is an amenable number.

21033520205 is a deficient number, since it is larger than the sum of its proper divisors (4206704047).

21033520205 is an equidigital number, since it uses as much as digits as its factorization.

21033520205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4206704046.

The product of its (nonzero) digits is 1800, while the sum is 23.

The spelling of 21033520205 in words is "twenty-one billion, thirty-three million, five hundred twenty thousand, two hundred five".