8320821 has 8 divisors (see below), whose sum is σ = 11114304. Its totient is φ = 5537280.

The previous prime is 8320817. The next prime is 8320831. The reversal of 8320821 is 1280238.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 8320821 - 2² = 8320817 is a prime.

It is a super-2 number, since 2×8320821² = 138472124228082, which contains 22 as substring.

8320821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 8320791 and 8320800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8320811) 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 7 ways as a sum of consecutive naturals, for example, 241 + ... + 4086.

It is an arithmetic number, because the mean of its divisors is an integer number (1389288).

Almost surely, 2^8320821 is an apocalyptic number.

It is an amenable number.

8320821 is a deficient number, since it is larger than the sum of its proper divisors (2793483).

8320821 is a wasteful number, since it uses less digits than its factorization.

8320821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4971.

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 8320821 is about 2884.5833321296. The cubic root of 8320821 is about 202.6385456399.

The spelling of 8320821 in words is "eight million, three hundred twenty thousand, eight hundred twenty-one".