4221440 has 80 divisors (see below), whose sum is σ = 10827432. Its totient is φ = 1572864.

The previous prime is 4221433. The next prime is 4221449. The reversal of 4221440 is 441224.

It can be written as a sum of positive squares in 4 ways, for example, as 3748096 + 473344 = 1936^2 + 688^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (17).

It is not an unprimeable number, because it can be changed into a prime (4221449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43472 + ... + 43568.

Almost surely, 2^4221440 is an apocalyptic number.

4221440 is a gapful number since it is divisible by the number (40) 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 4221440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5413716).

4221440 is an abundant number, since it is smaller than the sum of its proper divisors (6605992).

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

4221440 is an equidigital number, since it uses as much as digits as its factorization.

4221440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 121 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 4221440 is about 2054.6143190390. The cubic root of 4221440 is about 161.6169377404.

Adding to 4221440 its reverse (441224), we get a palindrome (4662664).

The spelling of 4221440 in words is "four million, two hundred twenty-one thousand, four hundred forty".