4021540 has 36 divisors (see below), whose sum is σ = 8929116. Its totient is φ = 1521216.

The previous prime is 4021531. The next prime is 4021543. The reversal of 4021540 is 451204.

It can be written as a sum of positive squares in 2 ways, for example, as 831744 + 3189796 = 912^2 + 1786^2 .

It is not an unprimeable number, because it can be changed into a prime (4021543) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6942 + ... + 7498.

It is an arithmetic number, because the mean of its divisors is an integer number (248031).

Almost surely, 2^4021540 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 4021540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4464558).

4021540 is an abundant number, since it is smaller than the sum of its proper divisors (4907576).

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

4021540 is a wasteful number, since it uses less digits than its factorization.

4021540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604 (or 583 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 4021540 is about 2005.3777698977. The cubic root of 4021540 is about 159.0245337457.

Adding to 4021540 its reverse (451204), we get a palindrome (4472744).

The spelling of 4021540 in words is "four million, twenty-one thousand, five hundred forty".