409509 has 16 divisors (see below), whose sum is σ = 628800. Its totient is φ = 263088.

The previous prime is 409499. The next prime is 409517. The reversal of 409509 is 905904.

It is a happy number.

It is not a de Polignac number, because 409509 - 2⁵ = 409477 is a prime.

It is a super-3 number, since 3×409509³ = 206021055333777687, which contains 333 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (409529) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 522 + ... + 1044.

It is an arithmetic number, because the mean of its divisors is an integer number (39300).

2⁴⁰⁹⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

409509 is a deficient number, since it is larger than the sum of its proper divisors (219291).

409509 is a wasteful number, since it uses less digits than its factorization.

409509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561 (or 555 counting only the distinct ones).

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

The square root of 409509 is about 639.9289023009. The cubic root of 409509 is about 74.2599211312.

The spelling of 409509 in words is "four hundred nine thousand, five hundred nine".