16890221 has 4 divisors (see below), whose sum is σ = 17779200. Its totient is φ = 16001244.

The previous prime is 16890191. The next prime is 16890233. The reversal of 16890221 is 12209861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16890221 - 2¹⁸ = 16628077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16890421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 444461 + ... + 444498.

It is an arithmetic number, because the mean of its divisors is an integer number (4444800).

Almost surely, 2^16890221 is an apocalyptic number.

It is an amenable number.

16890221 is a deficient number, since it is larger than the sum of its proper divisors (888979).

16890221 is an equidigital number, since it uses as much as digits as its factorization.

16890221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 888978.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 16890221 is about 4109.7714048351. The cubic root of 16890221 is about 256.5734874750.

The spelling of 16890221 in words is "sixteen million, eight hundred ninety thousand, two hundred twenty-one".