16819921 has 8 divisors (see below), whose sum is σ = 18040320. Its totient is φ = 15633072.

The previous prime is 16819909. The next prime is 16819927. The reversal of 16819921 is 12991861.

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 16819921 - 2⁵ = 16819889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16819927) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7345 + ... + 9358.

It is an arithmetic number, because the mean of its divisors is an integer number (2255040).

Almost surely, 2^16819921 is an apocalyptic number.

It is an amenable number.

16819921 is a deficient number, since it is larger than the sum of its proper divisors (1220399).

16819921 is a wasteful number, since it uses less digits than its factorization.

16819921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16775.

The product of its digits is 7776, while the sum is 37.

The square root of 16819921 is about 4101.2096995886. The cubic root of 16819921 is about 256.2170248268.

The spelling of 16819921 in words is "sixteen million, eight hundred nineteen thousand, nine hundred twenty-one".