561666164 has 24 divisors (see below), whose sum is σ = 1027618368. Its totient is φ = 268107840.

The previous prime is 561666137. The next prime is 561666167. The reversal of 561666164 is 461666165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561666167) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44744 + ... + 55904.

It is an arithmetic number, because the mean of its divisors is an integer number (42817432).

Almost surely, 2^561666164 is an apocalyptic number.

It is an amenable number.

561666164 is a deficient number, since it is larger than the sum of its proper divisors (465952204).

561666164 is a wasteful number, since it uses less digits than its factorization.

561666164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11735 (or 11733 counting only the distinct ones).

The product of its digits is 155520, while the sum is 41.

The square root of 561666164 is about 23699.4971254666. The cubic root of 561666164 is about 825.0737192772.

Subtracting from 561666164 its reverse (461666165), we obtain a palindrome (99999999).

The spelling of 561666164 in words is "five hundred sixty-one million, six hundred sixty-six thousand, one hundred sixty-four".