21536343305 has 4 divisors (see below), whose sum is σ = 25843611972. Its totient is φ = 17229074640.

The previous prime is 21536343289. The next prime is 21536343373. The reversal of 21536343305 is 50334363512.

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 5403279049 + 16133064256 = 73507^2 + 127016^2 .

It is not a de Polignac number, because 21536343305 - 2⁴ = 21536343289 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2153634326 + ... + 2153634335.

It is an arithmetic number, because the mean of its divisors is an integer number (6460902993).

Almost surely, 2^21536343305 is an apocalyptic number.

It is an amenable number.

21536343305 is a deficient number, since it is larger than the sum of its proper divisors (4307268667).

21536343305 is an equidigital number, since it uses as much as digits as its factorization.

21536343305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4307268666.

The product of its (nonzero) digits is 97200, while the sum is 35.

The spelling of 21536343305 in words is "twenty-one billion, five hundred thirty-six million, three hundred forty-three thousand, three hundred five".