561605505666 has 8 divisors (see below), whose sum is σ = 1123211011344. Its totient is φ = 187201835220.

The previous prime is 561605505653. The next prime is 561605505667. The reversal of 561605505666 is 666505506165.

It is a sphenic number, since it is the product of 3 distinct primes.

561605505666 is an admirable number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (561605505667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46800458800 + ... + 46800458811.

It is an arithmetic number, because the mean of its divisors is an integer number (140401376418).

Almost surely, 2^561605505666 is an apocalyptic number.

561605505666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

561605505666 is a wasteful number, since it uses less digits than its factorization.

561605505666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93600917616.

The product of its (nonzero) digits is 4860000, while the sum is 51.

The spelling of 561605505666 in words is "five hundred sixty-one billion, six hundred five million, five hundred five thousand, six hundred sixty-six".