219806 has 4 divisors (see below), whose sum is σ = 329712. Its totient is φ = 109902.

The previous prime is 219799. The next prime is 219809. The reversal of 219806 is 608912.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

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 219806.

It is not an unprimeable number, because it can be changed into a prime (219809) by changing a digit.

219806 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54950 + ... + 54953.

It is an arithmetic number, because the mean of its divisors is an integer number (82428).

2²¹⁹⁸⁰⁶ is an apocalyptic number.

219806 is a deficient number, since it is larger than the sum of its proper divisors (109906).

219806 is a wasteful number, since it uses less digits than its factorization.

219806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109905.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 219806 is about 468.8347256763. The cubic root of 219806 is about 60.3503575847.

The spelling of 219806 in words is "two hundred nineteen thousand, eight hundred six".