12391840 has 48 divisors (see below), whose sum is σ = 30005640. Its totient is φ = 4833280.

The previous prime is 12391831. The next prime is 12391867. The reversal of 12391840 is 4819321.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6574096 + 5817744 = 2564^2 + 2412^2 .

It is a junction number, because it is equal to n+sod(n) for n = 12391799 and 12391808.

It is an unprimeable number.

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, 5616 + ... + 7504.

Almost surely, 2^12391840 is an apocalyptic number.

12391840 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 12391840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15002820).

12391840 is an abundant number, since it is smaller than the sum of its proper divisors (17613800).

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

12391840 is a wasteful number, since it uses less digits than its factorization.

12391840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1945 (or 1937 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 12391840 is about 3520.2045395119. The cubic root of 12391840 is about 231.4081226806.

It can be divided in two parts, 12391 and 840, that added together give a palindrome (13231).

The spelling of 12391840 in words is "twelve million, three hundred ninety-one thousand, eight hundred forty".