561611720166 has 32 divisors (see below), whose sum is σ = 1283706136320. Its totient is φ = 160457715936.

The previous prime is 561611720147. The next prime is 561611720249. The reversal of 561611720166 is 661027116165.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4728885 + ... + 4846191.

It is an arithmetic number, because the mean of its divisors is an integer number (40115816760).

Almost surely, 2^561611720166 is an apocalyptic number.

561611720166 is an abundant number, since it is smaller than the sum of its proper divisors (722094416154).

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

561611720166 is a wasteful number, since it uses less digits than its factorization.

561611720166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231308.

The product of its (nonzero) digits is 90720, while the sum is 42.

The spelling of 561611720166 in words is "five hundred sixty-one billion, six hundred eleven million, seven hundred twenty thousand, one hundred sixty-six".