12391540 has 48 divisors (see below), whose sum is σ = 30248064. Its totient is φ = 4176000.

The previous prime is 12391501. The next prime is 12391541. The reversal of 12391540 is 4519321.

12391540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12391541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7815 + ... + 9265.

It is an arithmetic number, because the mean of its divisors is an integer number (630168).

Almost surely, 2^12391540 is an apocalyptic number.

12391540 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 12391540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15124032).

12391540 is an abundant number, since it is smaller than the sum of its proper divisors (17856524).

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

12391540 is a wasteful number, since it uses less digits than its factorization.

12391540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1528 (or 1526 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 12391540 is about 3520.1619280936. The cubic root of 12391540 is about 231.4062552421.

The spelling of 12391540 in words is "twelve million, three hundred ninety-one thousand, five hundred forty".