561566394 has 48 divisors (see below), whose sum is σ = 1290088800. Its totient is φ = 176046048.

The previous prime is 561566393. The next prime is 561566399. The reversal of 561566394 is 493665165.

561566394 is a `hidden beast` number, since 5 + 6 + 1 + 5 + 6 + 639 + 4 = 666.

561566394 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (561566393) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41632 + ... + 53444.

It is an arithmetic number, because the mean of its divisors is an integer number (26876850).

Almost surely, 2^561566394 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561566394, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (645044400).

561566394 is an abundant number, since it is smaller than the sum of its proper divisors (728522406).

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

561566394 is a wasteful number, since it uses less digits than its factorization.

561566394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11979 (or 11976 counting only the distinct ones).

The product of its digits is 583200, while the sum is 45.

The square root of 561566394 is about 23697.3921350008. The cubic root of 561566394 is about 825.0248631625.

The spelling of 561566394 in words is "five hundred sixty-one million, five hundred sixty-six thousand, three hundred ninety-four".