561215805 has 16 divisors (see below), whose sum is σ = 898470144. Its totient is φ = 299140160.

The previous prime is 561215789. The next prime is 561215807. The reversal of 561215805 is 508512165.

It is not a de Polignac number, because 561215805 - 2⁴ = 561215789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561215807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18067 + ... + 38063.

It is an arithmetic number, because the mean of its divisors is an integer number (56154384).

Almost surely, 2^561215805 is an apocalyptic number.

It is an amenable number.

561215805 is a deficient number, since it is larger than the sum of its proper divisors (337254339).

561215805 is a wasteful number, since it uses less digits than its factorization.

561215805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21876.

The product of its (nonzero) digits is 12000, while the sum is 33.

The square root of 561215805 is about 23689.9937737434. The cubic root of 561215805 is about 824.8531382290.

The spelling of 561215805 in words is "five hundred sixty-one million, two hundred fifteen thousand, eight hundred five".