16993321 has 2 divisors, whose sum is σ = 16993322. Its totient is φ = 16993320.

The previous prime is 16993313. The next prime is 16993349. The reversal of 16993321 is 12339961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16646400 + 346921 = 4080^2 + 589^2 .

It is a cyclic number.

It is not a de Polignac number, because 16993321 - 2³ = 16993313 is a prime.

It is not a weakly prime, because it can be changed into another prime (16993381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8496660 + 8496661.

It is an arithmetic number, because the mean of its divisors is an integer number (8496661).

Almost surely, 2^16993321 is an apocalyptic number.

It is an amenable number.

16993321 is a deficient number, since it is larger than the sum of its proper divisors (1).

16993321 is an equidigital number, since it uses as much as digits as its factorization.

16993321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8748, while the sum is 34.

The square root of 16993321 is about 4122.2955983287. The cubic root of 16993321 is about 257.0944809495.

The spelling of 16993321 in words is "sixteen million, nine hundred ninety-three thousand, three hundred twenty-one".