42003521 has 4 divisors (see below), whose sum is σ = 48004032. Its totient is φ = 36003012.

The previous prime is 42003491. The next prime is 42003539. The reversal of 42003521 is 12530024.

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 a cyclic number.

It is not a de Polignac number, because 42003521 - 2¹⁴ = 41987137 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 42003521.

It is not an unprimeable number, because it can be changed into a prime (42003551) 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, 3000245 + ... + 3000258.

It is an arithmetic number, because the mean of its divisors is an integer number (12001008).

Almost surely, 2^42003521 is an apocalyptic number.

It is an amenable number.

42003521 is a deficient number, since it is larger than the sum of its proper divisors (6000511).

42003521 is an equidigital number, since it uses as much as digits as its factorization.

42003521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6000510.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 42003521 is about 6481.0123437624. The cubic root of 42003521 is about 347.6123777806.

Adding to 42003521 its reverse (12530024), we get a palindrome (54533545).

It can be divided in two parts, 42003 and 521, that added together give a palindrome (42524).

The spelling of 42003521 in words is "forty-two million, three thousand, five hundred twenty-one".