56561009 has 4 divisors (see below), whose sum is σ = 56666100. Its totient is φ = 56455920.

The previous prime is 56561003. The next prime is 56561027. The reversal of 56561009 is 90016565.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90016565 = 5 ⋅18003313.

It can be written as a sum of positive squares in 2 ways, for example, as 21715600 + 34845409 = 4660^2 + 5903^2 .

It is a cyclic number.

It is not a de Polignac number, because 56561009 - 2⁴ = 56560993 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (56561003) 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, 51734 + ... + 52815.

It is an arithmetic number, because the mean of its divisors is an integer number (14166525).

Almost surely, 2^56561009 is an apocalyptic number.

It is an amenable number.

56561009 is a deficient number, since it is larger than the sum of its proper divisors (105091).

56561009 is a wasteful number, since it uses less digits than its factorization.

56561009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105090.

The product of its (nonzero) digits is 8100, while the sum is 32.

The square root of 56561009 is about 7520.7053525584. The cubic root of 56561009 is about 383.8595791007.

The spelling of 56561009 in words is "fifty-six million, five hundred sixty-one thousand, nine".