561543840 has 576 divisors, whose sum is σ = 2357776512. Its totient is φ = 124416000.

The previous prime is 561543839. The next prime is 561543859. The reversal of 561543840 is 48345165.

It is a happy number.

561543840 is a `hidden beast` number, since 5 + 615 + 4 + 38 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 561543795 and 561543804.

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 95 ways as a sum of consecutive naturals, for example, 5559790 + ... + 5559890.

It is an arithmetic number, because the mean of its divisors is an integer number (4093362).

Almost surely, 2^561543840 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 561543840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1178888256).

561543840 is an abundant number, since it is smaller than the sum of its proper divisors (1796232672).

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

561543840 is a wasteful number, since it uses less digits than its factorization.

561543840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 135 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 561543840 is about 23696.9162550742. The cubic root of 561543840 is about 825.0138179504.

It can be divided in two parts, 5615 and 43840, that added together give a triangular number (49455 = T₃₁₄).

The spelling of 561543840 in words is "five hundred sixty-one million, five hundred forty-three thousand, eight hundred forty".