861864 has 16 divisors (see below), whose sum is σ = 2154720. Its totient is φ = 287280.

The previous prime is 861857. The next prime is 861871. The reversal of 861864 is 468168.

It is an interprime number because it is at equal distance from previous prime (861857) and next prime (861871).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17932 + ... + 17979.

It is an arithmetic number, because the mean of its divisors is an integer number (134670).

2⁸⁶¹⁸⁶⁴ is an apocalyptic number.

It is an amenable number.

861864 is an abundant number, since it is smaller than the sum of its proper divisors (1292856).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

861864 is a wasteful number, since it uses less digits than its factorization.

861864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35920 (or 35916 counting only the distinct ones).

The product of its digits is 9216, while the sum is 33.

The square root of 861864 is about 928.3663070146. The cubic root of 861864 is about 95.1655101859.

The spelling of 861864 in words is "eight hundred sixty-one thousand, eight hundred sixty-four".