12421440 has 168 divisors, whose sum is σ = 45171360. Its totient is φ = 3124224.

The previous prime is 12421439. The next prime is 12421481. The reversal of 12421440 is 4412421.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 54607 + ... + 54833.

Almost surely, 2^12421440 is an apocalyptic number.

12421440 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 12421440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22585680).

12421440 is an abundant number, since it is smaller than the sum of its proper divisors (32749920).

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

12421440 is a wasteful number, since it uses less digits than its factorization.

12421440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269 (or 256 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 12421440 is about 3524.4063329872. The cubic root of 12421440 is about 231.5922286134.

Adding to 12421440 its reverse (4412421), we get a palindrome (16833861).

The spelling of 12421440 in words is "twelve million, four hundred twenty-one thousand, four hundred forty".