864117861 has 4 divisors (see below), whose sum is σ = 1152157152. Its totient is φ = 576078572.

The previous prime is 864117847. The next prime is 864117907. The reversal of 864117861 is 168711468.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 864117861 - 2⁷ = 864117733 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (864117811) 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 in 3 ways as a sum of consecutive naturals, for example, 144019641 + ... + 144019646.

It is an arithmetic number, because the mean of its divisors is an integer number (288039288).

Almost surely, 2^864117861 is an apocalyptic number.

It is an amenable number.

864117861 is a deficient number, since it is larger than the sum of its proper divisors (288039291).

864117861 is a wasteful number, since it uses less digits than its factorization.

864117861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288039290.

The product of its digits is 64512, while the sum is 42.

The square root of 864117861 is about 29395.8817013540. The cubic root of 864117861 is about 952.4839377015.

The spelling of 864117861 in words is "eight hundred sixty-four million, one hundred seventeen thousand, eight hundred sixty-one".