865644513 has 4 divisors (see below), whose sum is σ = 1154192688. Its totient is φ = 577096340.

The previous prime is 865644511. The next prime is 865644517. The reversal of 865644513 is 315446568.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 865644513 - 2¹ = 865644511 is a prime.

It is not an unprimeable number, because it can be changed into a prime (865644511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144274083 + ... + 144274088.

It is an arithmetic number, because the mean of its divisors is an integer number (288548172).

Almost surely, 2^865644513 is an apocalyptic number.

It is an amenable number.

865644513 is a deficient number, since it is larger than the sum of its proper divisors (288548175).

865644513 is a wasteful number, since it uses less digits than its factorization.

865644513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288548174.

The product of its digits is 345600, while the sum is 42.

The square root of 865644513 is about 29421.8373491528. The cubic root of 865644513 is about 953.0445309874.

The spelling of 865644513 in words is "eight hundred sixty-five million, six hundred forty-four thousand, five hundred thirteen".