40809 has 8 divisors (see below), whose sum is σ = 55552. Its totient is φ = 26640.

The previous prime is 40801. The next prime is 40813. The reversal of 40809 is 90804.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 40809 - 2³ = 40801 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 40809.

It is not an unprimeable number, because it can be changed into a prime (40801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72 + ... + 294.

It is an arithmetic number, because the mean of its divisors is an integer number (6944).

2⁴⁰⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

40809 is a deficient number, since it is larger than the sum of its proper divisors (14743).

40809 is a wasteful number, since it uses less digits than its factorization.

40809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 40809 is about 202.0123758585. The cubic root of 40809 is about 34.4285435529.

The spelling of 40809 in words is "forty thousand, eight hundred nine".