861905 has 8 divisors (see below), whose sum is σ = 1128384. Its totient is φ = 626800.

The previous prime is 861901. The next prime is 861907. The reversal of 861905 is 509168.

861905 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 861905 - 2² = 861901 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (861901) 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, 7781 + ... + 7890.

It is an arithmetic number, because the mean of its divisors is an integer number (141048).

2⁸⁶¹⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

861905 is a deficient number, since it is larger than the sum of its proper divisors (266479).

861905 is a wasteful number, since it uses less digits than its factorization.

861905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15687.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 861905 is about 928.3883885530. The cubic root of 861905 is about 95.1670192113.

It can be divided in two parts, 86 and 1905, that added together give a palindrome (1991).

The spelling of 861905 in words is "eight hundred sixty-one thousand, nine hundred five".