821324785 has 4 divisors (see below), whose sum is σ = 985589748. Its totient is φ = 657059824.

The previous prime is 821324773. The next prime is 821324789. The reversal of 821324785 is 587423128.

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 415181376 + 406143409 = 20376^2 + 20153^2 .

It is a cyclic number.

It is not a de Polignac number, because 821324785 - 2¹¹ = 821322737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821324789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82132474 + ... + 82132483.

It is an arithmetic number, because the mean of its divisors is an integer number (246397437).

Almost surely, 2^821324785 is an apocalyptic number.

It is an amenable number.

821324785 is a deficient number, since it is larger than the sum of its proper divisors (164264963).

821324785 is a wasteful number, since it uses less digits than its factorization.

821324785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164264962.

The product of its digits is 107520, while the sum is 40.

The square root of 821324785 is about 28658.7645407125. The cubic root of 821324785 is about 936.4939503449.

The spelling of 821324785 in words is "eight hundred twenty-one million, three hundred twenty-four thousand, seven hundred eighty-five".