21016586738305 has 4 divisors (see below), whose sum is σ = 25219904085972. Its totient is φ = 16813269390640.

The previous prime is 21016586738297. The next prime is 21016586738333. The reversal of 21016586738305 is 50383768561012.

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 11588911254001 + 9427675484304 = 3404249^2 + 3070452^2 .

It is not a de Polignac number, because 21016586738305 - 2³ = 21016586738297 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 (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2101658673826 + ... + 2101658673835.

It is an arithmetic number, because the mean of its divisors is an integer number (6304976021493).

Almost surely, 2^{21016586738305} is an apocalyptic number.

It is an amenable number.

21016586738305 is a deficient number, since it is larger than the sum of its proper divisors (4203317347667).

21016586738305 is an equidigital number, since it uses as much as digits as its factorization.

21016586738305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4203317347666.

The product of its (nonzero) digits is 7257600, while the sum is 55.

The spelling of 21016586738305 in words is "twenty-one trillion, sixteen billion, five hundred eighty-six million, seven hundred thirty-eight thousand, three hundred five".