865608520 has 80 divisors (see below), whose sum is σ = 2272339260. Its totient is φ = 296747136.

The previous prime is 865608487. The next prime is 865608521. The reversal of 865608520 is 25806568.

It can be written as a sum of positive squares in 2 ways, for example, as 858607204 + 7001316 = 29302^2 + 2646^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (865608521) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 91534 + ... + 100546.

Almost surely, 2^865608520 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 865608520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1136169630).

865608520 is an abundant number, since it is smaller than the sum of its proper divisors (1406730740).

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

865608520 is an equidigital number, since it uses as much as digits as its factorization.

865608520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9052 (or 9027 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 40.

The square root of 865608520 is about 29421.2256712735. The cubic root of 865608520 is about 953.0313217902.

The spelling of 865608520 in words is "eight hundred sixty-five million, six hundred eight thousand, five hundred twenty".