8420440 has 128 divisors (see below), whose sum is σ = 24105600. Its totient is φ = 2580480.

The previous prime is 8420413. The next prime is 8420441. The reversal of 8420440 is 440248.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8420441) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 138010 + ... + 138070.

It is an arithmetic number, because the mean of its divisors is an integer number (188325).

Almost surely, 2^8420440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8420440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12052800).

8420440 is an abundant number, since it is smaller than the sum of its proper divisors (15685160).

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

8420440 is a wasteful number, since it uses less digits than its factorization.

8420440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 121 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 22.

The square root of 8420440 is about 2901.7994417258. The cubic root of 8420440 is about 203.4440198814. Note that the first 3 decimals are identical.

Adding to 8420440 its reverse (440248), we get a palindrome (8860688).

The spelling of 8420440 in words is "eight million, four hundred twenty thousand, four hundred forty".