865115871 has 4 divisors (see below), whose sum is σ = 1153487832. Its totient is φ = 576743912.

The previous prime is 865115851. The next prime is 865115893. The reversal of 865115871 is 178511568.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 865115871 - 2¹⁸ = 864853727 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865115821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144185976 + ... + 144185981.

It is an arithmetic number, because the mean of its divisors is an integer number (288371958).

Almost surely, 2^865115871 is an apocalyptic number.

865115871 is a deficient number, since it is larger than the sum of its proper divisors (288371961).

865115871 is a wasteful number, since it uses less digits than its factorization.

865115871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288371960.

The product of its digits is 67200, while the sum is 42.

The square root of 865115871 is about 29412.8521398385. The cubic root of 865115871 is about 952.8504859902.

The spelling of 865115871 in words is "eight hundred sixty-five million, one hundred fifteen thousand, eight hundred seventy-one".