21616052061365 has 4 divisors (see below), whose sum is σ = 25939262473644. Its totient is φ = 17292841649088.

The previous prime is 21616052061347. The next prime is 21616052061413. The reversal of 21616052061365 is 56316025061612.

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 5868670981156 + 15747381080209 = 2422534^2 + 3968297^2 .

It is a cyclic number.

It is not a de Polignac number, because 21616052061365 - 2²² = 21616047867061 is a prime.

It is a Duffinian number.

It is a Curzon 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, 2161605206132 + ... + 2161605206141.

It is an arithmetic number, because the mean of its divisors is an integer number (6484815618411).

Almost surely, 2^{21616052061365} is an apocalyptic number.

It is an amenable number.

21616052061365 is a deficient number, since it is larger than the sum of its proper divisors (4323210412279).

21616052061365 is an equidigital number, since it uses as much as digits as its factorization.

21616052061365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4323210412278.

The product of its (nonzero) digits is 388800, while the sum is 44.

The spelling of 21616052061365 in words is "twenty-one trillion, six hundred sixteen billion, fifty-two million, sixty-one thousand, three hundred sixty-five".