865215 has 64 divisors (see below), whose sum is σ = 1814400. Its totient is φ = 387072.

The previous prime is 865213. The next prime is 865217. The reversal of 865215 is 512568.

865215 is a `hidden beast` number, since 8 + 652 + 1 + 5 = 666.

865215 is nontrivially palindromic in base 12.

It is an interprime number because it is at equal distance from previous prime (865213) and next prime (865217).

It is not a de Polignac number, because 865215 - 2¹ = 865213 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865211) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 29821 + ... + 29849.

It is an arithmetic number, because the mean of its divisors is an integer number (28350).

2⁸⁶⁵²¹⁵ is an apocalyptic number.

865215 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

865215 is an abundant number, since it is smaller than the sum of its proper divisors (949185).

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

865215 is a wasteful number, since it uses less digits than its factorization.

865215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73 (or 67 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 865215 is about 930.1693394216. The cubic root of 865215 is about 95.2886878614.

The spelling of 865215 in words is "eight hundred sixty-five thousand, two hundred fifteen".