4005021 has 4 divisors (see below), whose sum is σ = 5340032. Its totient is φ = 2670012.

The previous prime is 4005019. The next prime is 4005049. The reversal of 4005021 is 1205004.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 4005021 - 2¹ = 4005019 is a prime.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 4004988 and 4005006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4005091) 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, 667501 + ... + 667506.

It is an arithmetic number, because the mean of its divisors is an integer number (1335008).

Almost surely, 2^4005021 is an apocalyptic number.

It is an amenable number.

4005021 is a deficient number, since it is larger than the sum of its proper divisors (1335011).

4005021 is a wasteful number, since it uses less digits than its factorization.

4005021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1335010.

The product of its (nonzero) digits is 40, while the sum is 12.

The square root of 4005021 is about 2001.2548563339. The cubic root of 4005021 is about 158.8064969308.

The spelling of 4005021 in words is "four million, five thousand, twenty-one".