561111209 has 2 divisors, whose sum is σ = 561111210. Its totient is φ = 561111208.

The previous prime is 561111157. The next prime is 561111223. The reversal of 561111209 is 902111165.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 559795600 + 1315609 = 23660^2 + 1147^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-561111209 is a prime.

It is not a weakly prime, because it can be changed into another prime (561113209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280555604 + 280555605.

It is an arithmetic number, because the mean of its divisors is an integer number (280555605).

Almost surely, 2^561111209 is an apocalyptic number.

It is an amenable number.

561111209 is a deficient number, since it is larger than the sum of its proper divisors (1).

561111209 is an equidigital number, since it uses as much as digits as its factorization.

561111209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 26.

The square root of 561111209 is about 23687.7860721512. The cubic root of 561111209 is about 824.8018913358.

The spelling of 561111209 in words is "five hundred sixty-one million, one hundred eleven thousand, two hundred nine".