8561665861 has 8 divisors (see below), whose sum is σ = 9789212160. Its totient is φ = 7335232368.

The previous prime is 8561665831. The next prime is 8561665891. The reversal of 8561665861 is 1685661658.

8561665861 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (8561665831) and next prime (8561665891).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 8561665861 - 2⁷ = 8561665733 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 8561665799 and 8561665808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8561665811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 261646 + ... + 292543.

It is an arithmetic number, because the mean of its divisors is an integer number (1223651520).

Almost surely, 2^8561665861 is an apocalyptic number.

It is an amenable number.

8561665861 is a deficient number, since it is larger than the sum of its proper divisors (1227546299).

8561665861 is a wasteful number, since it uses less digits than its factorization.

8561665861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 556403.

The product of its digits is 2073600, while the sum is 52.

The square root of 8561665861 is about 92529.2702932429. The cubic root of 8561665861 is about 2045.7509341397.

The spelling of 8561665861 in words is "eight billion, five hundred sixty-one million, six hundred sixty-five thousand, eight hundred sixty-one".