12381440 has 72 divisors (see below), whose sum is σ = 31457160. Its totient is φ = 4653056.

The previous prime is 12381427. The next prime is 12381443. The reversal of 12381440 is 4418321.

It can be written as a sum of positive squares in 4 ways, for example, as 984064 + 11397376 = 992^2 + 3376^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12381443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21476 + ... + 22044.

It is an arithmetic number, because the mean of its divisors is an integer number (436905).

Almost surely, 2^12381440 is an apocalyptic number.

12381440 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 12381440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15728580).

12381440 is an abundant number, since it is smaller than the sum of its proper divisors (19075720).

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

12381440 is an equidigital number, since it uses as much as digits as its factorization.

12381440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 607 (or 593 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 12381440 is about 3518.7270425539. The cubic root of 12381440 is about 231.3433672163.

Adding to 12381440 its reverse (4418321), we get a palindrome (16799761).

It can be divided in two parts, 12381 and 440, that added together give a palindrome (12821).

The spelling of 12381440 in words is "twelve million, three hundred eighty-one thousand, four hundred forty".