109809 has 24 divisors (see below), whose sum is σ = 191520. Its totient is φ = 61992.

The previous prime is 109807. The next prime is 109819. The reversal of 109809 is 908901.

109809 is nontrivially palindromic in base 11.

It is not a de Polignac number, because 109809 - 2¹ = 109807 is a prime.

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

It is a Curzon number.

109809 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 109809.

It is not an unprimeable number, because it can be changed into a prime (109807) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1282 + ... + 1364.

It is an arithmetic number, because the mean of its divisors is an integer number (7980).

2¹⁰⁹⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

109809 is a deficient number, since it is larger than the sum of its proper divisors (81711).

109809 is an equidigital number, since it uses as much as digits as its factorization.

109809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106 (or 93 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 109809 is about 331.3744105992. The cubic root of 109809 is about 47.8864503467.

The spelling of 109809 in words is "one hundred nine thousand, eight hundred nine".