2165981671361 has 2 divisors, whose sum is σ = 2165981671362. Its totient is φ = 2165981671360.

The previous prime is 2165981671351. The next prime is 2165981671391. The reversal of 2165981671361 is 1631761895612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2165297535025 + 684136336 = 1471495^2 + 26156^2 .

It is a cyclic number.

It is not a de Polignac number, because 2165981671361 - 2¹⁸ = 2165981409217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2165981671297 and 2165981671306.

It is not a weakly prime, because it can be changed into another prime (2165981671331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1082990835680 + 1082990835681.

It is an arithmetic number, because the mean of its divisors is an integer number (1082990835681).

Almost surely, 2^{2165981671361} is an apocalyptic number.

It is an amenable number.

2165981671361 is a deficient number, since it is larger than the sum of its proper divisors (1).

2165981671361 is an equidigital number, since it uses as much as digits as its factorization.

2165981671361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3265920, while the sum is 56.

The spelling of 2165981671361 in words is "two trillion, one hundred sixty-five billion, nine hundred eighty-one million, six hundred seventy-one thousand, three hundred sixty-one".