12840 has 32 divisors (see below), whose sum is σ = 38880. Its totient is φ = 3392.

The previous prime is 12829. The next prime is 12841. The reversal of 12840 is 4821.

12840 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (15).

12840 is strictly pandigital in base 6.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (12841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67 + ... + 173.

It is an arithmetic number, because the mean of its divisors is an integer number (1215).

2¹²⁸⁴⁰ is an apocalyptic number.

12840 is a gapful number since it is divisible by the number (10) 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 12840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19440).

12840 is an abundant number, since it is smaller than the sum of its proper divisors (26040).

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

12840 is a wasteful number, since it uses less digits than its factorization.

12840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 12840 is about 113.3137237937. The cubic root of 12840 is about 23.4164833821.

The spelling of 12840 in words is "twelve thousand, eight hundred forty".