4042021 has 4 divisors (see below), whose sum is σ = 4052044. Its totient is φ = 4032000.

The previous prime is 4042019. The next prime is 4042033. The reversal of 4042021 is 1202404.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1185921 + 2856100 = 1089^2 + 1690^2 .

It is a cyclic number.

It is not a de Polignac number, because 4042021 - 2¹ = 4042019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 4041992 and 4042010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4042001) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 4380 + ... + 5221.

It is an arithmetic number, because the mean of its divisors is an integer number (1013011).

Almost surely, 2^4042021 is an apocalyptic number.

It is an amenable number.

4042021 is a deficient number, since it is larger than the sum of its proper divisors (10023).

4042021 is an equidigital number, since it uses as much as digits as its factorization.

4042021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10022.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 4042021 is about 2010.4778039063. The cubic root of 4042021 is about 159.2940381302.

Adding to 4042021 its reverse (1202404), we get a palindrome (5244425).

The spelling of 4042021 in words is "four million, forty-two thousand, twenty-one".