561997800 has 576 divisors, whose sum is σ = 2404846080. Its totient is φ = 114462720.

The previous prime is 561997771. The next prime is 561997817. The reversal of 561997800 is 8799165.

561997800 is a `hidden beast` number, since 561 + 9 + 9 + 7 + 80 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a zygodrome in base 3.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 7698564 + ... + 7698636.

It is an arithmetic number, because the mean of its divisors is an integer number (4175080).

Almost surely, 2^561997800 is an apocalyptic number.

561997800 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 561997800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1202423040).

561997800 is an abundant number, since it is smaller than the sum of its proper divisors (1842848280).

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

561997800 is a wasteful number, since it uses less digits than its factorization.

561997800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 45.

The square root of 561997800 is about 23706.4927815145. The cubic root of 561997800 is about 825.2360756906.

The spelling of 561997800 in words is "five hundred sixty-one million, nine hundred ninety-seven thousand, eight hundred".