5661661551109 has 2 divisors, whose sum is σ = 5661661551110. Its totient is φ = 5661661551108.

The previous prime is 5661661551067. The next prime is 5661661551163. The reversal of 5661661551109 is 9011551661665.

5661661551109 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5261633130625 + 400028420484 = 2293825^2 + 632478^2 .

It is a cyclic number.

It is not a de Polignac number, because 5661661551109 - 2³⁷ = 5524222597637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5661661551199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2830830775554 + 2830830775555.

It is an arithmetic number, because the mean of its divisors is an integer number (2830830775555).

Almost surely, 2^{5661661551109} is an apocalyptic number.

It is an amenable number.

5661661551109 is a deficient number, since it is larger than the sum of its proper divisors (1).

5661661551109 is an equidigital number, since it uses as much as digits as its factorization.

5661661551109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458000, while the sum is 52.

The spelling of 5661661551109 in words is "five trillion, six hundred sixty-one billion, six hundred sixty-one million, five hundred fifty-one thousand, one hundred nine".