2106805 has 4 divisors (see below), whose sum is σ = 2528172. Its totient is φ = 1685440.

The previous prime is 2106781. The next prime is 2106809. The reversal of 2106805 is 5086012.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 603729 + 1503076 = 777^2 + 1226^2 .

It is not a de Polignac number, because 2106805 - 2⁵ = 2106773 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2106809) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 210676 + ... + 210685.

It is an arithmetic number, because the mean of its divisors is an integer number (632043).

2^2106805 is an apocalyptic number.

It is an amenable number.

2106805 is a deficient number, since it is larger than the sum of its proper divisors (421367).

2106805 is an equidigital number, since it uses as much as digits as its factorization.

2106805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421366.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 2106805 is about 1451.4837236428. The cubic root of 2106805 is about 128.1960902330.

The spelling of 2106805 in words is "two million, one hundred six thousand, eight hundred five".