561666365 has 16 divisors (see below), whose sum is σ = 726385968. Its totient is φ = 414460416.

The previous prime is 561666361. The next prime is 561666367. The reversal of 561666365 is 563666165.

It can be written as a sum of positive squares in 8 ways, for example, as 92813956 + 468852409 = 9634^2 + 21653^2 .

It is a cyclic number.

It is not a de Polignac number, because 561666365 - 2² = 561666361 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561666361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 122087 + ... + 126603.

It is an arithmetic number, because the mean of its divisors is an integer number (45399123).

Almost surely, 2^561666365 is an apocalyptic number.

It is an amenable number.

561666365 is a deficient number, since it is larger than the sum of its proper divisors (164719603).

561666365 is a wasteful number, since it uses less digits than its factorization.

561666365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6448.

The product of its digits is 583200, while the sum is 44.

The square root of 561666365 is about 23699.5013660625. The cubic root of 561666365 is about 825.0738176985.

The spelling of 561666365 in words is "five hundred sixty-one million, six hundred sixty-six thousand, three hundred sixty-five".