6815440 has 20 divisors (see below), whose sum is σ = 15846084. Its totient is φ = 2726144.

The previous prime is 6815399. The next prime is 6815447. The reversal of 6815440 is 445186.

It can be written as a sum of positive squares in 2 ways, for example, as 3415104 + 3400336 = 1848^2 + 1844^2 .

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 = 6815399 and 6815408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6815447) 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, 42517 + ... + 42676.

Almost surely, 2^6815440 is an apocalyptic number.

It is an amenable number.

6815440 is an abundant number, since it is smaller than the sum of its proper divisors (9030644).

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

6815440 is a wasteful number, since it uses less digits than its factorization.

6815440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85206 (or 85200 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 6815440 is about 2610.6397683327. The cubic root of 6815440 is about 189.5969294547.

The spelling of 6815440 in words is "six million, eight hundred fifteen thousand, four hundred forty".