213806 has 4 divisors (see below), whose sum is σ = 320712. Its totient is φ = 106902.

The previous prime is 213799. The next prime is 213821. The reversal of 213806 is 608312.

213806 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a plaindrome in base 11.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 53450 + ... + 53453.

It is an arithmetic number, because the mean of its divisors is an integer number (80178).

2²¹³⁸⁰⁶ is an apocalyptic number.

213806 is a deficient number, since it is larger than the sum of its proper divisors (106906).

213806 is a wasteful number, since it uses less digits than its factorization.

213806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106905.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 213806 is about 462.3916089204. The cubic root of 213806 is about 59.7961601245.

The spelling of 213806 in words is "two hundred thirteen thousand, eight hundred six".