6840 has 48 divisors (see below), whose sum is σ = 23400. Its totient is φ = 1728.

The previous prime is 6833. The next prime is 6841. The reversal of 6840 is 486.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 351 + ... + 369.

2⁶⁸⁴⁰ is an apocalyptic number.

6840 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 6840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11700).

6840 is an abundant number, since it is smaller than the sum of its proper divisors (16560).

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

6840 is a wasteful number, since it uses less digits than its factorization.

6840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36 (or 29 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 6840 is about 82.7042925125. The cubic root of 6840 is about 18.9824399161.

The spelling of 6840 in words is "six thousand, eight hundred forty".