820346321 has 4 divisors (see below), whose sum is σ = 820468644. Its totient is φ = 820224000.

The previous prime is 820346297. The next prime is 820346347. The reversal of 820346321 is 123643028.

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 16000000 + 804346321 = 4000^2 + 28361^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820346321 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (820346921) 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, 50480 + ... + 64721.

It is an arithmetic number, because the mean of its divisors is an integer number (205117161).

Almost surely, 2^820346321 is an apocalyptic number.

It is an amenable number.

820346321 is a deficient number, since it is larger than the sum of its proper divisors (122323).

820346321 is a wasteful number, since it uses less digits than its factorization.

820346321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122322.

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 820346321 is about 28641.6885151696. The cubic root of 820346321 is about 936.1219132999.

Adding to 820346321 its reverse (123643028), we get a palindrome (943989349).

The spelling of 820346321 in words is "eight hundred twenty million, three hundred forty-six thousand, three hundred twenty-one".