540809 has 2 divisors, whose sum is σ = 540810. Its totient is φ = 540808.

The previous prime is 540803. The next prime is 540823. The reversal of 540809 is 908045.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 511225 + 29584 = 715^2 + 172^2 .

It is a cyclic number.

It is not a de Polignac number, because 540809 - 2¹⁶ = 475273 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (540803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 270404 + 270405.

It is an arithmetic number, because the mean of its divisors is an integer number (270405).

2⁵⁴⁰⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

540809 is a deficient number, since it is larger than the sum of its proper divisors (1).

540809 is an equidigital number, since it uses as much as digits as its factorization.

540809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 540809 is about 735.3971716018. The cubic root of 540809 is about 81.4731742041.

Subtracting 540809 from its reverse (908045), we obtain a square (367236 = 606²).

The spelling of 540809 in words is "five hundred forty thousand, eight hundred nine".