6509840 has 20 divisors (see below), whose sum is σ = 15135564. Its totient is φ = 2603904.

The previous prime is 6509821. The next prime is 6509843. The reversal of 6509840 is 489056.

It can be written as a sum of positive squares in 2 ways, for example, as 4343056 + 2166784 = 2084^2 + 1472^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 6509797 and 6509806.

It is not an unprimeable number, because it can be changed into a prime (6509843) 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, 40607 + ... + 40766.

Almost surely, 2^6509840 is an apocalyptic number.

It is an amenable number.

6509840 is an abundant number, since it is smaller than the sum of its proper divisors (8625724).

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

6509840 is a wasteful number, since it uses less digits than its factorization.

6509840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81386 (or 81380 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 6509840 is about 2551.4388097699. The cubic root of 6509840 is about 186.7196844867.

The spelling of 6509840 in words is "six million, five hundred nine thousand, eight hundred forty".