219809 has 2 divisors, whose sum is σ = 219810. Its totient is φ = 219808.

The previous prime is 219799. The next prime is 219823. The reversal of 219809 is 908912.

219809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112225 + 107584 = 335^2 + 328^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-219809 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 219809.

It is not a weakly prime, because it can be changed into another prime (219829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109904 + 109905.

It is an arithmetic number, because the mean of its divisors is an integer number (109905).

2²¹⁹⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

219809 is a deficient number, since it is larger than the sum of its proper divisors (1).

219809 is an equidigital number, since it uses as much as digits as its factorization.

219809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 219809 is about 468.8379250871. The cubic root of 219809 is about 60.3506321454.

The spelling of 219809 in words is "two hundred nineteen thousand, eight hundred nine".