13440 has 64 divisors (see below), whose sum is σ = 48960. Its totient is φ = 3072.
The previous prime is 13421. The next prime is 13441. The reversal of 13440 is 4431.
It is a tau number, because it is divible by the number of its divisors (64).
It is a Harshad number since it is a multiple of its sum of digits (12).
It is an Ulam number.
It is a nialpdrome in base 8.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (13441) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1917 + ... + 1923.
It is an arithmetic number, because the mean of its divisors is an integer number (765).
213440 is an apocalyptic number.
13440 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 13440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24480).
13440 is an abundant number, since it is smaller than the sum of its proper divisors (35520).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
13440 is an equidigital number, since it uses as much as digits as its factorization.
13440 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 29 (or 17 counting only the distinct ones).
The product of its (nonzero) digits is 48, while the sum is 12.
The square root of 13440 is about 115.9310139695. The cubic root of 13440 is about 23.7756878111.
Adding to 13440 its reverse (4431), we get a palindrome (17871).
Subtracting from 13440 its reverse (4431), we obtain a palindrome (9009).
The spelling of 13440 in words is "thirteen thousand, four hundred forty".
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