561864 has 32 divisors (see below), whose sum is σ = 1441440. Its totient is φ = 182400.

The previous prime is 561839. The next prime is 561907. The reversal of 561864 is 468165.

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 699 + ... + 1269.

It is an arithmetic number, because the mean of its divisors is an integer number (45045).

2⁵⁶¹⁸⁶⁴ 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 561864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (720720).

561864 is an abundant number, since it is smaller than the sum of its proper divisors (879576).

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

561864 is a wasteful number, since it uses less digits than its factorization.

561864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 621 (or 617 counting only the distinct ones).

The product of its digits is 5760, while the sum is 30.

The square root of 561864 is about 749.5758800815. The cubic root of 561864 is about 82.5170579971.

The spelling of 561864 in words is "five hundred sixty-one thousand, eight hundred sixty-four".