28327221 has 24 divisors (see below), whose sum is σ = 44324280. Its totient is φ = 17329536.

The previous prime is 28327217. The next prime is 28327259. The reversal of 28327221 is 12272382.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 16112196 + 12215025 = 4014^2 + 3495^2 .

It is not a de Polignac number, because 28327221 - 2² = 28327217 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 (28327121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22435 + ... + 23663.

It is an arithmetic number, because the mean of its divisors is an integer number (1846845).

Almost surely, 2^28327221 is an apocalyptic number.

It is an amenable number.

28327221 is a deficient number, since it is larger than the sum of its proper divisors (15997059).

28327221 is a wasteful number, since it uses less digits than its factorization.

28327221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1445 (or 1442 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

The square root of 28327221 is about 5322.3322895137. The cubic root of 28327221 is about 304.8372185212.

The spelling of 28327221 in words is "twenty-eight million, three hundred twenty-seven thousand, two hundred twenty-one".