28369221 has 8 divisors (see below), whose sum is σ = 39130080. Its totient is φ = 18260592.

The previous prime is 28369213. The next prime is 28369249. The reversal of 28369221 is 12296382.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28369221 - 2³ = 28369213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28369921) 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 7 ways as a sum of consecutive naturals, for example, 162955 + ... + 163128.

It is an arithmetic number, because the mean of its divisors is an integer number (4891260).

Almost surely, 2^28369221 is an apocalyptic number.

It is an amenable number.

28369221 is a deficient number, since it is larger than the sum of its proper divisors (10760859).

28369221 is a wasteful number, since it uses less digits than its factorization.

28369221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326115.

The product of its digits is 10368, while the sum is 33.

The square root of 28369221 is about 5326.2764667261. The cubic root of 28369221 is about 304.9878020742.

The spelling of 28369221 in words is "twenty-eight million, three hundred sixty-nine thousand, two hundred twenty-one".