561637800 has 240 divisors, whose sum is σ = 2005509660. Its totient is φ = 145566720.

The previous prime is 561637771. The next prime is 561637801. The reversal of 561637800 is 8736165.

561637800 is a `hidden beast` number, since 5 + 616 + 37 + 8 + 0 + 0 = 666.

561637800 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 175986756 + 385651044 = 13266^2 + 19638^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561637801) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 598932 + ... + 599868.

Almost surely, 2^561637800 is an apocalyptic number.

561637800 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 561637800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1002754830).

561637800 is an abundant number, since it is smaller than the sum of its proper divisors (1443871860).

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

561637800 is a wasteful number, since it uses less digits than its factorization.

561637800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1002 (or 984 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 561637800 is about 23698.8987085898. The cubic root of 561637800 is about 825.0598303716.

The spelling of 561637800 in words is "five hundred sixty-one million, six hundred thirty-seven thousand, eight hundred".