16813321 has 12 divisors (see below), whose sum is σ = 20037780. Its totient is φ = 14058240.

The previous prime is 16813319. The next prime is 16813339. The reversal of 16813321 is 12331861.

It can be written as a sum of positive squares in 2 ways, for example, as 5664400 + 11148921 = 2380^2 + 3339^2 .

It is not a de Polignac number, because 16813321 - 2¹ = 16813319 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16813361) 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 11 ways as a sum of consecutive naturals, for example, 2176 + ... + 6193.

It is an arithmetic number, because the mean of its divisors is an integer number (1669815).

Almost surely, 2^16813321 is an apocalyptic number.

It is an amenable number.

16813321 is a deficient number, since it is larger than the sum of its proper divisors (3224459).

16813321 is an equidigital number, since it uses as much as digits as its factorization.

16813321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8424 (or 8417 counting only the distinct ones).

The product of its digits is 864, while the sum is 25.

The square root of 16813321 is about 4100.4049799989. The cubic root of 16813321 is about 256.1835079513.

The spelling of 16813321 in words is "sixteen million, eight hundred thirteen thousand, three hundred twenty-one".