561209 has 8 divisors (see below), whose sum is σ = 617952. Its totient is φ = 505440.

The previous prime is 561199. The next prime is 561229. The reversal of 561209 is 902165.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-561209 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1637 + ... + 1949.

It is an arithmetic number, because the mean of its divisors is an integer number (77244).

2⁵⁶¹²⁰⁹ is an apocalyptic number.

It is an amenable number.

561209 is a deficient number, since it is larger than the sum of its proper divisors (56743).

561209 is a wasteful number, since it uses less digits than its factorization.

561209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 487.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 561209 is about 749.1388389344. The cubic root of 561209 is about 82.4849804308.

The spelling of 561209 in words is "five hundred sixty-one thousand, two hundred nine".