812028109 has 4 divisors (see below), whose sum is σ = 812168316. Its totient is φ = 811887904.

The previous prime is 812028089. The next prime is 812028143. The reversal of 812028109 is 901820218.

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 160655625 + 651372484 = 12675^2 + 25522^2 .

It is a cyclic number.

It is not a de Polignac number, because 812028109 - 2⁹ = 812027597 is a prime.

It is a super-2 number, since 2×812028109² = 1318779299612231762, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) 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 (812028149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61024 + ... + 73129.

It is an arithmetic number, because the mean of its divisors is an integer number (203042079).

Almost surely, 2^812028109 is an apocalyptic number.

It is an amenable number.

812028109 is a deficient number, since it is larger than the sum of its proper divisors (140207).

812028109 is a wasteful number, since it uses less digits than its factorization.

812028109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140206.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 812028109 is about 28496.1069095412. The cubic root of 812028109 is about 932.9471041252.

The spelling of 812028109 in words is "eight hundred twelve million, twenty-eight thousand, one hundred nine".