4221540 has 72 divisors (see below), whose sum is σ = 13104000. Its totient is φ = 1099584.

The previous prime is 4221533. The next prime is 4221541. The reversal of 4221540 is 451224.

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

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (4221541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8211 + ... + 8709.

It is an arithmetic number, because the mean of its divisors is an integer number (182000).

Almost surely, 2^4221540 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 4221540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6552000).

4221540 is an abundant number, since it is smaller than the sum of its proper divisors (8882460).

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

4221540 is a wasteful number, since it uses less digits than its factorization.

4221540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561 (or 556 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 4221540 is about 2054.6386543624. The cubic root of 4221540 is about 161.6182138899.

Adding to 4221540 its reverse (451224), we get a palindrome (4672764).

It can be divided in two parts, 4221 and 540, that added together give a square (4761 = 69²).

The spelling of 4221540 in words is "four million, two hundred twenty-one thousand, five hundred forty".