4005521 has 4 divisors (see below), whose sum is σ = 4313652. Its totient is φ = 3697392.

The previous prime is 4005499. The next prime is 4005527. The reversal of 4005521 is 1255004.

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 160000 + 3845521 = 400^2 + 1961^2 .

It is a cyclic number.

It is not a de Polignac number, because 4005521 - 2⁶ = 4005457 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 4005521.

It is not an unprimeable number, because it can be changed into a prime (4005527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 154046 + ... + 154071.

It is an arithmetic number, because the mean of its divisors is an integer number (1078413).

Almost surely, 2^4005521 is an apocalyptic number.

It is an amenable number.

4005521 is a deficient number, since it is larger than the sum of its proper divisors (308131).

4005521 is a wasteful number, since it uses less digits than its factorization.

4005521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308130.

The product of its (nonzero) digits is 200, while the sum is 17.

The square root of 4005521 is about 2001.3797740559. The cubic root of 4005521 is about 158.8131052977.

The spelling of 4005521 in words is "four million, five thousand, five hundred twenty-one".