561026661 has 32 divisors (see below), whose sum is σ = 850698240. Its totient is φ = 326026944.

The previous prime is 561026651. The next prime is 561026701. The reversal of 561026661 is 166620165.

It is not a de Polignac number, because 561026661 - 2⁹ = 561026149 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561026621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 270916 + ... + 272978.

It is an arithmetic number, because the mean of its divisors is an integer number (26584320).

Almost surely, 2^561026661 is an apocalyptic number.

It is an amenable number.

561026661 is a deficient number, since it is larger than the sum of its proper divisors (289671579).

561026661 is a wasteful number, since it uses less digits than its factorization.

561026661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2465.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 561026661 is about 23686.0013721185. The cubic root of 561026661 is about 824.7604623214.

The spelling of 561026661 in words is "five hundred sixty-one million, twenty-six thousand, six hundred sixty-one".