561505660 has 48 divisors (see below), whose sum is σ = 1215621792. Its totient is φ = 217728000.

The previous prime is 561505649. The next prime is 561505669. The reversal of 561505660 is 66505165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561505669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 131560 + ... + 135760.

It is an arithmetic number, because the mean of its divisors is an integer number (25325454).

Almost surely, 2^561505660 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 561505660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (607810896).

561505660 is an abundant number, since it is smaller than the sum of its proper divisors (654116132).

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

561505660 is a wasteful number, since it uses less digits than its factorization.

561505660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4414 (or 4412 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 34.

The square root of 561505660 is about 23696.1106513284. The cubic root of 561505660 is about 824.9951196528.

The spelling of 561505660 in words is "five hundred sixty-one million, five hundred five thousand, six hundred sixty".