540004021 has 4 divisors (see below), whose sum is σ = 541953772. Its totient is φ = 538054272.

The previous prime is 540003991. The next prime is 540004037. The reversal of 540004021 is 120400045.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120400045 = 5 ⋅24080009.

It can be written as a sum of positive squares in 2 ways, for example, as 128482225 + 411521796 = 11335^2 + 20286^2 .

It is a cyclic number.

It is not a de Polignac number, because 540004021 - 2⁹ = 540003509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 540003986 and 540004004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (540004321) 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, 974460 + ... + 975013.

It is an arithmetic number, because the mean of its divisors is an integer number (135488443).

Almost surely, 2^540004021 is an apocalyptic number.

It is an amenable number.

540004021 is a deficient number, since it is larger than the sum of its proper divisors (1949751).

540004021 is a wasteful number, since it uses less digits than its factorization.

540004021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1949750.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 540004021 is about 23237.9865952281. The cubic root of 540004021 is about 814.3273062092.

Adding to 540004021 its reverse (120400045), we get a palindrome (660404066).

The spelling of 540004021 in words is "five hundred forty million, four thousand, twenty-one".