561685009 has 4 divisors (see below), whose sum is σ = 563457204. Its totient is φ = 559912816.

The previous prime is 561684943. The next prime is 561685013. The reversal of 561685009 is 900586165.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 110250000 + 451435009 = 10500^2 + 21247^2 .

It is a cyclic number.

It is not a de Polignac number, because 561685009 - 2²⁷ = 427467281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561685409) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 885622 + ... + 886255.

It is an arithmetic number, because the mean of its divisors is an integer number (140864301).

Almost surely, 2^561685009 is an apocalyptic number.

It is an amenable number.

561685009 is a deficient number, since it is larger than the sum of its proper divisors (1772195).

561685009 is a wasteful number, since it uses less digits than its factorization.

561685009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1772194.

The product of its (nonzero) digits is 64800, while the sum is 40.

The square root of 561685009 is about 23699.8947044074. The cubic root of 561685009 is about 825.0829467871.

The spelling of 561685009 in words is "five hundred sixty-one million, six hundred eighty-five thousand, nine".