561661128 has 300 divisors, whose sum is σ = 1936933515. Its totient is φ = 152028576.

The previous prime is 561661123. The next prime is 561661159. The reversal of 561661128 is 821166165.

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.

561661128 is a `hidden beast` number, since 5 + 6 + 16 + 611 + 28 = 666.

It can be written as a sum of positive squares in only one way, i.e., 280830564 + 280830564 = 16758^2 + 16758^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=16758.

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

It is a junction number, because it is equal to n+sod(n) for n = 561661092 and 561661101.

It is not an unprimeable number, because it can be changed into a prime (561661123) by changing a digit.

It is a polite number, since it can be written in 74 ways as a sum of consecutive naturals, for example, 29561103 + ... + 29561121.

Almost surely, 2^561661128 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 561661128

561661128 is an abundant number, since it is smaller than the sum of its proper divisors (1375272387).

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

561661128 is an equidigital number, since it uses as much as digits as its factorization.

561661128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84 (or 31 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 561661128 is about 23699.3908782483. The cubic root of 561661128 is about 825.0712533500.

The spelling of 561661128 in words is "five hundred sixty-one million, six hundred sixty-one thousand, one hundred twenty-eight".