561109531 has 4 divisors (see below), whose sum is σ = 594115992. Its totient is φ = 528103072.

The previous prime is 561109513. The next prime is 561109561. The reversal of 561109531 is 135901165.

561109531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 561109531 - 2⁵ = 561109499 is a prime.

It is a super-2 number, since 2×561109531² = 629687811558079922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 561109493 and 561109502.

It is not an unprimeable number, because it can be changed into a prime (561109561) 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, 16503205 + ... + 16503238.

It is an arithmetic number, because the mean of its divisors is an integer number (148528998).

Almost surely, 2^561109531 is an apocalyptic number.

561109531 is a deficient number, since it is larger than the sum of its proper divisors (33006461).

561109531 is a wasteful number, since it uses less digits than its factorization.

561109531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33006460.

The product of its (nonzero) digits is 4050, while the sum is 31.

The square root of 561109531 is about 23687.7506530274. The cubic root of 561109531 is about 824.8010691465.

The spelling of 561109531 in words is "five hundred sixty-one million, one hundred nine thousand, five hundred thirty-one".