6806640 has 80 divisors (see below), whose sum is σ = 21427200. Its totient is φ = 1787136.

The previous prime is 6806633. The next prime is 6806651. The reversal of 6806640 is 466086.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 6806598 and 6806607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18781 + ... + 19139.

It is an arithmetic number, because the mean of its divisors is an integer number (267840).

Almost surely, 2^6806640 is an apocalyptic number.

6806640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6806640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10713600).

6806640 is an abundant number, since it is smaller than the sum of its proper divisors (14620560).

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

6806640 is a wasteful number, since it uses less digits than its factorization.

6806640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454 (or 448 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 6806640 is about 2608.9538133129. The cubic root of 6806640 is about 189.5152926815.

The spelling of 6806640 in words is "six million, eight hundred six thousand, six hundred forty".