28194221 has 16 divisors (see below), whose sum is σ = 32140800. Its totient is φ = 24499200.

The previous prime is 28194193. The next prime is 28194223. The reversal of 28194221 is 12249182.

It is a de Polignac number, because none of the positive numbers 2^k-28194221 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28194223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29885 + ... + 30813.

It is an arithmetic number, because the mean of its divisors is an integer number (2008800).

Almost surely, 2^28194221 is an apocalyptic number.

It is an amenable number.

28194221 is a deficient number, since it is larger than the sum of its proper divisors (3946579).

28194221 is a wasteful number, since it uses less digits than its factorization.

28194221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1060.

The product of its digits is 2304, while the sum is 29.

The square root of 28194221 is about 5309.8230667321. The cubic root of 28194221 is about 304.3593864012.

The spelling of 28194221 in words is "twenty-eight million, one hundred ninety-four thousand, two hundred twenty-one".