8561909 has 2 divisors, whose sum is σ = 8561910. Its totient is φ = 8561908.

The previous prime is 8561893. The next prime is 8561939. The reversal of 8561909 is 9091658.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5654884 + 2907025 = 2378^2 + 1705^2 .

It is a cyclic number.

It is not a de Polignac number, because 8561909 - 2⁴ = 8561893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8561939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4280954 + 4280955.

It is an arithmetic number, because the mean of its divisors is an integer number (4280955).

Almost surely, 2^8561909 is an apocalyptic number.

It is an amenable number.

8561909 is a deficient number, since it is larger than the sum of its proper divisors (1).

8561909 is an equidigital number, since it uses as much as digits as its factorization.

8561909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 8561909 is about 2926.0739908622. The cubic root of 8561909 is about 204.5770299418.

The spelling of 8561909 in words is "eight million, five hundred sixty-one thousand, nine hundred nine".