812209 has 4 divisors (see below), whose sum is σ = 860004. Its totient is φ = 764416.

The previous prime is 812191. The next prime is 812213. The reversal of 812209 is 902218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 902218 = 2 ⋅451109.

It can be written as a sum of positive squares in 2 ways, for example, as 595984 + 216225 = 772^2 + 465^2 .

It is a cyclic number.

It is not a de Polignac number, because 812209 - 2⁷ = 812081 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 812209.

It is not an unprimeable number, because it can be changed into a prime (812249) 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, 23872 + ... + 23905.

It is an arithmetic number, because the mean of its divisors is an integer number (215001).

2⁸¹²²⁰⁹ is an apocalyptic number.

It is an amenable number.

812209 is a deficient number, since it is larger than the sum of its proper divisors (47795).

812209 is a wasteful number, since it uses less digits than its factorization.

812209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47794.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 812209 is about 901.2263866532. The cubic root of 812209 is about 93.3016374800.

Subtracting 812209 from its reverse (902218), we obtain a palindrome (90009).

It can be divided in two parts, 81 and 2209, that multiplied together give a square (178929 = 423²).

The spelling of 812209 in words is "eight hundred twelve thousand, two hundred nine".