16828221 has 4 divisors (see below), whose sum is σ = 22437632. Its totient is φ = 11218812.

The previous prime is 16828213. The next prime is 16828237. The reversal of 16828221 is 12282861.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12282861 = 3 ⋅4094287.

It is not a de Polignac number, because 16828221 - 2³ = 16828213 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 (16828261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2804701 + ... + 2804706.

It is an arithmetic number, because the mean of its divisors is an integer number (5609408).

Almost surely, 2^16828221 is an apocalyptic number.

It is an amenable number.

16828221 is a deficient number, since it is larger than the sum of its proper divisors (5609411).

16828221 is an equidigital number, since it uses as much as digits as its factorization.

16828221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5609410.

The product of its digits is 3072, while the sum is 30.

The square root of 16828221 is about 4102.2214713494. The cubic root of 16828221 is about 256.2591623930.

The spelling of 16828221 in words is "sixteen million, eight hundred twenty-eight thousand, two hundred twenty-one".