561785220 has 120 divisors (see below), whose sum is σ = 1768353048. Its totient is φ = 149299200.

The previous prime is 561785207. The next prime is 561785221. The reversal of 561785220 is 22587165.

It is a happy number.

561785220 is a `hidden beast` number, since 5 + 61 + 78 + 522 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 131056704 + 430728516 = 11448^2 + 20754^2 .

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

It is not an unprimeable number, because it can be changed into a prime (561785221) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 876100 + ... + 876740.

Almost surely, 2^561785220 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 561785220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (884176524).

561785220 is an abundant number, since it is smaller than the sum of its proper divisors (1206567828).

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

561785220 is a wasteful number, since it uses less digits than its factorization.

561785220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1203 (or 1192 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The square root of 561785220 is about 23702.0087756291. The cubic root of 561785220 is about 825.1320119329.

The spelling of 561785220 in words is "five hundred sixty-one million, seven hundred eighty-five thousand, two hundred twenty".