320000561 has 4 divisors (see below), whose sum is σ = 320062500. Its totient is φ = 319938624.

The previous prime is 320000533. The next prime is 320000573. The reversal of 320000561 is 165000023.

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 301682161 + 18318400 = 17369^2 + 4280^2 .

It is a cyclic number.

It is not a de Polignac number, because 320000561 - 2⁶ = 320000497 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 (320000521) 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, 22436 + ... + 33813.

It is an arithmetic number, because the mean of its divisors is an integer number (80015625).

Almost surely, 2^320000561 is an apocalyptic number.

It is an amenable number.

320000561 is a deficient number, since it is larger than the sum of its proper divisors (61939).

320000561 is an equidigital number, since it uses as much as digits as its factorization.

320000561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61938.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 320000561 is about 17888.5595004181. The cubic root of 320000561 is about 683.9907783773.

Adding to 320000561 its reverse (165000023), we get a palindrome (485000584).

The spelling of 320000561 in words is "three hundred twenty million, five hundred sixty-one", and thus it is an aban number.