13840 has 20 divisors (see below), whose sum is σ = 32364. Its totient is φ = 5504.

The previous prime is 13831. The next prime is 13841. The reversal of 13840 is 4831.

It can be written as a sum of positive squares in 2 ways, for example, as 9216 + 4624 = 96^2 + 68^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a nialpdrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (13841) 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 3 ways as a sum of consecutive naturals, for example, 7 + ... + 166.

2¹³⁸⁴⁰ is an apocalyptic number.

13840 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 13840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16182).

13840 is an abundant number, since it is smaller than the sum of its proper divisors (18524).

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

13840 is a wasteful number, since it uses less digits than its factorization.

13840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 13840 is about 117.6435293588. The cubic root of 13840 is about 24.0092556893.

Subtracting from 13840 its sum of digits (16), we obtain a cube (13824 = 24³).

Subtracting from 13840 its reverse (4831), we obtain a palindrome (9009).

The spelling of 13840 in words is "thirteen thousand, eight hundred forty".