561111160661 has 4 divisors (see below), whose sum is σ = 561115348332. Its totient is φ = 561106972992.

The previous prime is 561111160657. The next prime is 561111160663. The reversal of 561111160661 is 166061111165.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166061111165 = 5 ⋅33212222233.

It can be written as a sum of positive squares in 2 ways, for example, as 379818294436 + 181292866225 = 616294^2 + 425785^2 .

It is a cyclic number.

It is not a de Polignac number, because 561111160661 - 2² = 561111160657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561111160663) 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 in 3 ways as a sum of consecutive naturals, for example, 1885970 + ... + 2163123.

It is an arithmetic number, because the mean of its divisors is an integer number (140278837083).

Almost surely, 2^561111160661 is an apocalyptic number.

It is an amenable number.

561111160661 is a deficient number, since it is larger than the sum of its proper divisors (4187671).

561111160661 is a wasteful number, since it uses less digits than its factorization.

561111160661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4187670.

The product of its (nonzero) digits is 6480, while the sum is 35.

The spelling of 561111160661 in words is "five hundred sixty-one billion, one hundred eleven million, one hundred sixty thousand, six hundred sixty-one".