561665440 has 144 divisors (see below), whose sum is σ = 1594059264. Its totient is φ = 186278400.

The previous prime is 561665413. The next prime is 561665453. The reversal of 561665440 is 44566165.

It is a self number, because there is not a number n which added to its sum of digits gives 561665440.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 241885 + ... + 244195.

It is an arithmetic number, because the mean of its divisors is an integer number (11069856).

Almost surely, 2^561665440 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 561665440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (797029632).

561665440 is an abundant number, since it is smaller than the sum of its proper divisors (1032393824).

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

561665440 is a wasteful number, since it uses less digits than its factorization.

561665440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2371 (or 2356 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 37.

The square root of 561665440 is about 23699.4818508760. The cubic root of 561665440 is about 825.0733647643.

The spelling of 561665440 in words is "five hundred sixty-one million, six hundred sixty-five thousand, four hundred forty".