561689856 has 576 divisors, whose sum is σ = 2197708800. Its totient is φ = 137355264.

The previous prime is 561689833. The next prime is 561689857. The reversal of 561689856 is 658986165.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561689857) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11950825 + ... + 11950871.

Almost surely, 2^561689856 is an apocalyptic number.

561689856 is a gapful number since it is divisible by the number (56) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561689856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1098854400).

561689856 is an abundant number, since it is smaller than the sum of its proper divisors (1636018944).

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

561689856 is a wasteful number, since it uses less digits than its factorization.

561689856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111 (or 91 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 54.

The square root of 561689856 is about 23699.9969620251. The cubic root of 561689856 is about 825.0853201017.

It can be divided in two parts, 5616 and 89856, that multiplied together give a square (504631296 = 22464²).

The spelling of 561689856 in words is "five hundred sixty-one million, six hundred eighty-nine thousand, eight hundred fifty-six".