561665329 has 8 divisors (see below), whose sum is σ = 596825928. Its totient is φ = 526740480.

The previous prime is 561665311. The next prime is 561665333. The reversal of 561665329 is 923566165.

It can be written as a sum of positive squares in 4 ways, for example, as 354305329 + 207360000 = 18823^2 + 14400^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 561665329 - 2⁵ = 561665297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561665389) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54012 + ... + 63565.

It is an arithmetic number, because the mean of its divisors is an integer number (74603241).

Almost surely, 2^561665329 is an apocalyptic number.

It is an amenable number.

561665329 is a deficient number, since it is larger than the sum of its proper divisors (35160599).

561665329 is a wasteful number, since it uses less digits than its factorization.

561665329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117875.

The product of its digits is 291600, while the sum is 43.

The square root of 561665329 is about 23699.4795090525. The cubic root of 561665329 is about 825.0733104122.

The spelling of 561665329 in words is "five hundred sixty-one million, six hundred sixty-five thousand, three hundred twenty-nine".