102809 has 8 divisors (see below), whose sum is σ = 123840. Its totient is φ = 83376.

The previous prime is 102797. The next prime is 102811. The reversal of 102809 is 908201.

102809 is an esthetic number in base 4, because in such base its adjacent digits differ by 1.

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

It is a cyclic number.

It is not a de Polignac number, because 102809 - 2⁴ = 102793 is a prime.

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 102809.

It is not an unprimeable number, because it can be changed into a prime (102829) 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, 254 + ... + 519.

It is an arithmetic number, because the mean of its divisors is an integer number (15480).

2¹⁰²⁸⁰⁹ is an apocalyptic number.

102809 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

102809 is a deficient number, since it is larger than the sum of its proper divisors (21031).

102809 is an equidigital number, since it uses as much as digits as its factorization.

102809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 799.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 102809 is about 320.6384256448. The cubic root of 102809 is about 46.8464887359.

The spelling of 102809 in words is "one hundred two thousand, eight hundred nine".