2105666165549 has 2 divisors, whose sum is σ = 2105666165550. Its totient is φ = 2105666165548.

The previous prime is 2105666165507. The next prime is 2105666165563. The reversal of 2105666165549 is 9455616665012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1457066268100 + 648599897449 = 1207090^2 + 805357^2 .

It is a cyclic number.

It is not a de Polignac number, because 2105666165549 - 2²⁴ = 2105649388333 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2105666165494 and 2105666165503.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2105666165569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1052833082774 + 1052833082775.

It is an arithmetic number, because the mean of its divisors is an integer number (1052833082775).

Almost surely, 2^{2105666165549} is an apocalyptic number.

It is an amenable number.

2105666165549 is a deficient number, since it is larger than the sum of its proper divisors (1).

2105666165549 is an equidigital number, since it uses as much as digits as its factorization.

2105666165549 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664000, while the sum is 56.

The spelling of 2105666165549 in words is "two trillion, one hundred five billion, six hundred sixty-six million, one hundred sixty-five thousand, five hundred forty-nine".