5665561049921 has 2 divisors, whose sum is σ = 5665561049922. Its totient is φ = 5665561049920.

The previous prime is 5665561049861. The next prime is 5665561049989. The reversal of 5665561049921 is 1299401655665.

It is a happy number.

5665561049921 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., 5591976349696 + 73584700225 = 2364736^2 + 271265^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-5665561049921 is a prime.

It is not a weakly prime, because it can be changed into another prime (5665561049021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2832780524960 + 2832780524961.

It is an arithmetic number, because the mean of its divisors is an integer number (2832780524961).

Almost surely, 2^{5665561049921} is an apocalyptic number.

It is an amenable number.

5665561049921 is a deficient number, since it is larger than the sum of its proper divisors (1).

5665561049921 is an equidigital number, since it uses as much as digits as its factorization.

5665561049921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496000, while the sum is 59.

The spelling of 5665561049921 in words is "five trillion, six hundred sixty-five billion, five hundred sixty-one million, forty-nine thousand, nine hundred twenty-one".