561660 has 96 divisors (see below), whose sum is σ = 1838592. Its totient is φ = 126720.

The previous prime is 561607. The next prime is 561667. The reversal of 561660 is 66165.

561660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 561660.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561667) by changing a digit.

561660 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15162 + ... + 15198.

It is an arithmetic number, because the mean of its divisors is an integer number (19152).

2⁵⁶¹⁶⁶⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (919296).

561660 is an abundant number, since it is smaller than the sum of its proper divisors (1276932).

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

561660 is a wasteful number, since it uses less digits than its factorization.

561660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 561660 is about 749.4397907771. The cubic root of 561660 is about 82.5070701012.

It can be divided in two parts, 561 and 660, that added together give a palindrome (1221).

The spelling of 561660 in words is "five hundred sixty-one thousand, six hundred sixty".