40509 has 12 divisors (see below), whose sum is σ = 66976. Its totient is φ = 23112.

The previous prime is 40507. The next prime is 40519. The reversal of 40509 is 90504.

It is not a de Polignac number, because 40509 - 2¹ = 40507 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 40491 and 40500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40507) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 259 + ... + 384.

2⁴⁰⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

40509 is a deficient number, since it is larger than the sum of its proper divisors (26467).

40509 is a wasteful number, since it uses less digits than its factorization.

40509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656 (or 653 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 40509 is about 201.2684774126. The cubic root of 40509 is about 34.3439708976.

The spelling of 40509 in words is "forty thousand, five hundred nine".