861861 has 48 divisors (see below), whose sum is σ = 1608768. Its totient is φ = 403200.

The previous prime is 861857. The next prime is 861871. The reversal of 861861 is 168168.

861861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 861861 - 2² = 861857 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 (861871) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21001 + ... + 21041.

It is an arithmetic number, because the mean of its divisors is an integer number (33516).

2⁸⁶¹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

861861 is a deficient number, since it is larger than the sum of its proper divisors (746907).

861861 is a wasteful number, since it uses less digits than its factorization.

861861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82 (or 75 counting only the distinct ones).

The product of its digits is 2304, while the sum is 30.

The square root of 861861 is about 928.3646912717. The cubic root of 861861 is about 95.1653997676.

The spelling of 861861 in words is "eight hundred sixty-one thousand, eight hundred sixty-one".