12321540 has 216 divisors, whose sum is σ = 47803392. Its totient is φ = 2540160.

The previous prime is 12321511. The next prime is 12321541. The reversal of 12321540 is 4512321.

12321540 is a `hidden beast` number, since 123 + 2 + 1 + 540 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (12321541) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 96957 + ... + 97083.

It is an arithmetic number, because the mean of its divisors is an integer number (221312).

Almost surely, 2^12321540 is an apocalyptic number.

12321540 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 12321540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23901696).

12321540 is an abundant number, since it is smaller than the sum of its proper divisors (35481852).

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

12321540 is a wasteful number, since it uses less digits than its factorization.

12321540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167 (or 155 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 12321540 is about 3510.2051222115. The cubic root of 12321540 is about 230.9696929936.

Adding to 12321540 its reverse (4512321), we get a palindrome (16833861).

It can be divided in two parts, 1232 and 1540, that added together give a palindrome (2772).

The spelling of 12321540 in words is "twelve million, three hundred twenty-one thousand, five hundred forty".