865871 has 2 divisors, whose sum is σ = 865872. Its totient is φ = 865870.

The previous prime is 865867. The next prime is 865877. The reversal of 865871 is 178568.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 865871 - 2² = 865867 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (865877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432935 + 432936.

It is an arithmetic number, because the mean of its divisors is an integer number (432936).

2⁸⁶⁵⁸⁷¹ is an apocalyptic number.

865871 is a deficient number, since it is larger than the sum of its proper divisors (1).

865871 is an equidigital number, since it uses as much as digits as its factorization.

865871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 35.

The square root of 865871 is about 930.5218965720. The cubic root of 865871 is about 95.3127641845.

The spelling of 865871 in words is "eight hundred sixty-five thousand, eight hundred seventy-one".