540509 has 2 divisors, whose sum is σ = 540510. Its totient is φ = 540508.

The previous prime is 540469. The next prime is 540511. The reversal of 540509 is 905045.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 525625 + 14884 = 725^2 + 122^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-540509 is a prime.

Together with 540511, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p₄₄₆₀₉ and since 540509 and 44609 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (540539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 270254 + 270255.

It is an arithmetic number, because the mean of its divisors is an integer number (270255).

2⁵⁴⁰⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

540509 is a deficient number, since it is larger than the sum of its proper divisors (1).

540509 is an equidigital number, since it uses as much as digits as its factorization.

540509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 540509 is about 735.1931718943. The cubic root of 540509 is about 81.4581063624.

The spelling of 540509 in words is "five hundred forty thousand, five hundred nine".