561666051601 has 2 divisors, whose sum is σ = 561666051602. Its totient is φ = 561666051600.

The previous prime is 561666051577. The next prime is 561666051647. The reversal of 561666051601 is 106150666165.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 358489587600 + 203176464001 = 598740^2 + 450751^2 .

It is a cyclic number.

It is not a de Polignac number, because 561666051601 - 2⁷ = 561666051473 is a prime.

It is not a weakly prime, because it can be changed into another prime (561666051671) 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, 280833025800 + 280833025801.

It is an arithmetic number, because the mean of its divisors is an integer number (280833025801).

Almost surely, 2^561666051601 is an apocalyptic number.

It is an amenable number.

561666051601 is a deficient number, since it is larger than the sum of its proper divisors (1).

561666051601 is an equidigital number, since it uses as much as digits as its factorization.

561666051601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 194400, while the sum is 43.

The spelling of 561666051601 in words is "five hundred sixty-one billion, six hundred sixty-six million, fifty-one thousand, six hundred one".