509409 has 20 divisors (see below), whose sum is σ = 803440. Its totient is φ = 320760.

The previous prime is 509393. The next prime is 509413. The reversal of 509409 is 904905.

509409 = T₂₂₂ + T₂₂₃ + ... + T₂₄₀.

It is a happy number.

It is not a de Polignac number, because 509409 - 2⁴ = 509393 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (509429) 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 19 ways as a sum of consecutive naturals, for example, 1374 + ... + 1704.

It is an arithmetic number, because the mean of its divisors is an integer number (40172).

2⁵⁰⁹⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

509409 is a deficient number, since it is larger than the sum of its proper divisors (294031).

509409 is a wasteful number, since it uses less digits than its factorization.

509409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362 (or 353 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 509409 is about 713.7289401446. The cubic root of 509409 is about 79.8648238044.

The spelling of 509409 in words is "five hundred nine thousand, four hundred nine".