6891840 has 84 divisors (see below), whose sum is σ = 23714964. Its totient is φ = 1837056.

The previous prime is 6891823. The next prime is 6891869. The reversal of 6891840 is 481986.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1016064 + 5875776 = 1008^2 + 2424^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6891795 and 6891804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1684 + ... + 4076.

It is an arithmetic number, because the mean of its divisors is an integer number (282321).

Almost surely, 2^6891840 is an apocalyptic number.

6891840 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 6891840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11857482).

6891840 is an abundant number, since it is smaller than the sum of its proper divisors (16823124).

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

6891840 is a wasteful number, since it uses less digits than its factorization.

6891840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2416 (or 2403 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 6891840 is about 2625.2314183706. The cubic root of 6891840 is about 190.3027491020.

The spelling of 6891840 in words is "six million, eight hundred ninety-one thousand, eight hundred forty".