16820321 has 8 divisors (see below), whose sum is σ = 19843584. Its totient is φ = 13952160.

The previous prime is 16820317. The next prime is 16820333. The reversal of 16820321 is 12302861.

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

It is a cyclic number.

It is not a de Polignac number, because 16820321 - 2² = 16820317 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16820341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38540 + ... + 38973.

It is an arithmetic number, because the mean of its divisors is an integer number (2480448).

Almost surely, 2^16820321 is an apocalyptic number.

It is an amenable number.

16820321 is a deficient number, since it is larger than the sum of its proper divisors (3023263).

16820321 is an equidigital number, since it uses as much as digits as its factorization.

16820321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77551.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 16820321 is about 4101.2584653982. The cubic root of 16820321 is about 256.2190558708.

The spelling of 16820321 in words is "sixteen million, eight hundred twenty thousand, three hundred twenty-one".