8121440 has 48 divisors (see below), whose sum is σ = 19359648. Its totient is φ = 3219456.

The previous prime is 8121439. The next prime is 8121499. The reversal of 8121440 is 441218.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a plaindrome in base 14.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30749 + ... + 31011.

It is an arithmetic number, because the mean of its divisors is an integer number (403326).

Almost surely, 2^8121440 is an apocalyptic number.

8121440 is a gapful number since it is divisible by the number (80) 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 8121440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9679824).

8121440 is an abundant number, since it is smaller than the sum of its proper divisors (11238208).

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

8121440 is a wasteful number, since it uses less digits than its factorization.

8121440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 471 (or 463 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 8121440 is about 2849.8140290201. The cubic root of 8121440 is about 201.0069220325.

Adding to 8121440 its reverse (441218), we get a palindrome (8562658).

The spelling of 8121440 in words is "eight million, one hundred twenty-one thousand, four hundred forty".