6389840 has 20 divisors (see below), whose sum is σ = 14856564. Its totient is φ = 2555904.

The previous prime is 6389821. The next prime is 6389849. The reversal of 6389840 is 489836.

It can be written as a sum of positive squares in 2 ways, for example, as 1336336 + 5053504 = 1156^2 + 2248^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a d-powerful number, because it can be written as 6 + 3¹⁰ + 8⁵ + 9⁴ + 8⁷ + 4¹¹ + 0 .

It is a junction number, because it is equal to n+sod(n) for n = 6389794 and 6389803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6389849) 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, 39857 + ... + 40016.

Almost surely, 2^6389840 is an apocalyptic number.

It is an amenable number.

6389840 is an abundant number, since it is smaller than the sum of its proper divisors (8466724).

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

6389840 is a wasteful number, since it uses less digits than its factorization.

6389840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79886 (or 79880 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 6389840 is about 2527.8132842439. The cubic root of 6389840 is about 185.5652543459.

The spelling of 6389840 in words is "six million, three hundred eighty-nine thousand, eight hundred forty".