16680321 has 24 divisors (see below), whose sum is σ = 27665664. Its totient is φ = 9486720.

The previous prime is 16680311. The next prime is 16680331. The reversal of 16680321 is 12308661.

16680321 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (16680311) and next prime (16680331).

It is not a de Polignac number, because 16680321 - 2⁵ = 16680289 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16680311) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16585 + ... + 17561.

It is an arithmetic number, because the mean of its divisors is an integer number (1152736).

Almost surely, 2^16680321 is an apocalyptic number.

It is an amenable number.

16680321 is a deficient number, since it is larger than the sum of its proper divisors (10985343).

16680321 is a wasteful number, since it uses less digits than its factorization.

16680321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1261 (or 1258 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 16680321 is about 4084.1548697374. The cubic root of 16680321 is about 255.5062147198.

Adding to 16680321 its reverse (12308661), we get a palindrome (28988982).

The spelling of 16680321 in words is "sixteen million, six hundred eighty thousand, three hundred twenty-one".