6391865 has 4 divisors (see below), whose sum is σ = 7670244. Its totient is φ = 5113488.

The previous prime is 6391841. The next prime is 6391877. The reversal of 6391865 is 5681936.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1229881 + 5161984 = 1109^2 + 2272^2 .

It is a cyclic number.

It is not a de Polignac number, because 6391865 - 2²² = 2197561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 639182 + ... + 639191.

It is an arithmetic number, because the mean of its divisors is an integer number (1917561).

Almost surely, 2^6391865 is an apocalyptic number.

It is an amenable number.

6391865 is a deficient number, since it is larger than the sum of its proper divisors (1278379).

6391865 is a wasteful number, since it uses less digits than its factorization.

6391865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1278378.

The product of its digits is 38880, while the sum is 38.

The square root of 6391865 is about 2528.2137963392. The cubic root of 6391865 is about 185.5848547299.

The spelling of 6391865 in words is "six million, three hundred ninety-one thousand, eight hundred sixty-five".