2160865556221 has 2 divisors, whose sum is σ = 2160865556222. Its totient is φ = 2160865556220.

The previous prime is 2160865556219. The next prime is 2160865556231. The reversal of 2160865556221 is 1226555680612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2143629804996 + 17235751225 = 1464114^2 + 131285^2 .

It is a cyclic number.

It is not a de Polignac number, because 2160865556221 - 2¹ = 2160865556219 is a prime.

Together with 2160865556219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2160865556231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080432778110 + 1080432778111.

It is an arithmetic number, because the mean of its divisors is an integer number (1080432778111).

Almost surely, 2^{2160865556221} is an apocalyptic number.

It is an amenable number.

2160865556221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2160865556221 is an equidigital number, since it uses as much as digits as its factorization.

2160865556221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728000, while the sum is 49.

The spelling of 2160865556221 in words is "two trillion, one hundred sixty billion, eight hundred sixty-five million, five hundred fifty-six thousand, two hundred twenty-one".