561832209 has 9 divisors (see below), whose sum is σ = 811638139. Its totient is φ = 374507400.

The previous prime is 561832207. The next prime is 561832213. The reversal of 561832209 is 902238165.

The square root of 561832209 is 23703.

It is a perfect power (a square), and thus also a powerful number.

561832209 is a `hidden beast` number, since 5 + 618 + 32 + 2 + 0 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 386004609 + 175827600 = 19647^2 + 13260^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 561832209 - 2¹ = 561832207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561832207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 67159 + ... + 75059.

Almost surely, 2^561832209 is an apocalyptic number.

561832209 is the 23703-rd square number.

561832209 is the 11852-nd centered octagonal number.

It is an amenable number.

561832209 is a deficient number, since it is larger than the sum of its proper divisors (249805930).

561832209 is an frugal number, since it uses more digits than its factorization.

561832209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15808 (or 7904 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The cubic root of 561832209 is about 825.1550166008.

Multiplying 561832209 by its sum of digits (36), we get a square (20225959524 = 142218²).

The spelling of 561832209 in words is "five hundred sixty-one million, eight hundred thirty-two thousand, two hundred nine".