561800000 has 126 divisors (see below), whose sum is σ = 1420225506. Its totient is φ = 220480000.

The previous prime is 561799993. The next prime is 561800009. The reversal of 561800000 is 8165.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 9 ways, for example, as 522762496 + 39037504 = 22864^2 + 6248^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561800009) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 10599974 + ... + 10600026.

It is an arithmetic number, because the mean of its divisors is an integer number (11271631).

Almost surely, 2^561800000 is an apocalyptic number.

561800000 is a gapful number since it is divisible by the number (50) 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 561800000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (710112753).

561800000 is an abundant number, since it is smaller than the sum of its proper divisors (858425506).

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

561800000 is an frugal number, since it uses more digits than its factorization.

561800000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 561800000 is about 23702.3205614978. The cubic root of 561800000 is about 825.1392479985.

Multiplying 561800000 by its sum of digits (20), we get a square (11236000000 = 106000²).

561800000 divided by its sum of digits (20) gives a square (28090000 = 5300²).

Adding to 561800000 its reverse (8165), we get a palindrome (561808165).

The spelling of 561800000 in words is "five hundred sixty-one million, eight hundred thousand".