8561999 has 4 divisors (see below), whose sum is σ = 9065664. Its totient is φ = 8058336.

The previous prime is 8561963. The next prime is 8562023. The reversal of 8561999 is 9991658.

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 8561999 - 2²⁰ = 7513423 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8561909) 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 in 3 ways as a sum of consecutive naturals, for example, 251807 + ... + 251840.

It is an arithmetic number, because the mean of its divisors is an integer number (2266416).

Almost surely, 2^8561999 is an apocalyptic number.

8561999 is a deficient number, since it is larger than the sum of its proper divisors (503665).

8561999 is a wasteful number, since it uses less digits than its factorization.

8561999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503664.

The product of its digits is 174960, while the sum is 47.

The square root of 8561999 is about 2926.0893697903. The cubic root of 8561999 is about 204.5777467550.

The spelling of 8561999 in words is "eight million, five hundred sixty-one thousand, nine hundred ninety-nine".