812129641 has 4 divisors (see below), whose sum is σ = 812191300. Its totient is φ = 812067984.

The previous prime is 812129533. The next prime is 812129663. The reversal of 812129641 is 146921218.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 523265625 + 288864016 = 22875^2 + 16996^2 .

It is a cyclic number.

It is not a de Polignac number, because 812129641 - 2¹¹ = 812127593 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 812129597 and 812129606.

It is not an unprimeable number, because it can be changed into a prime (812129741) 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, 2226 + ... + 40363.

It is an arithmetic number, because the mean of its divisors is an integer number (203047825).

Almost surely, 2^812129641 is an apocalyptic number.

It is an amenable number.

812129641 is a deficient number, since it is larger than the sum of its proper divisors (61659).

812129641 is a wasteful number, since it uses less digits than its factorization.

812129641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61658.

The product of its digits is 6912, while the sum is 34.

The square root of 812129641 is about 28497.8883603680. Note that the first 3 decimals coincide. The cubic root of 812129641 is about 932.9859862102.

The spelling of 812129641 in words is "eight hundred twelve million, one hundred twenty-nine thousand, six hundred forty-one".