540021 has 4 divisors (see below), whose sum is σ = 720032. Its totient is φ = 360012.

The previous prime is 539993. The next prime is 540041. The reversal of 540021 is 120045.

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 540021 - 2⁹ = 539509 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 539979 and 540006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (540041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90001 + ... + 90006.

It is an arithmetic number, because the mean of its divisors is an integer number (180008).

2⁵⁴⁰⁰²¹ is an apocalyptic number.

It is an amenable number.

540021 is a deficient number, since it is larger than the sum of its proper divisors (180011).

540021 is a wasteful number, since it uses less digits than its factorization.

540021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180010.

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

The square root of 540021 is about 734.8612113862. The cubic root of 540021 is about 81.4335840910.

Adding to 540021 its reverse (120045), we get a palindrome (660066).

The spelling of 540021 in words is "five hundred forty thousand, twenty-one".