28321216 has 84 divisors (see below), whose sum is σ = 71405496. Its totient is φ = 11020800.

The previous prime is 28321199. The next prime is 28321217. The reversal of 28321216 is 61212382.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28321217) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34086 + ... + 34906.

Almost surely, 2^28321216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28321216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35702748).

28321216 is an abundant number, since it is smaller than the sum of its proper divisors (43084280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28321216 is a wasteful number, since it uses less digits than its factorization.

28321216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 858 (or 841 counting only the distinct ones).

The product of its digits is 1152, while the sum is 25.

The square root of 28321216 is about 5321.7681272299. The cubic root of 28321216 is about 304.8156764991.

Adding to 28321216 its reverse (61212382), we get a palindrome (89533598).

The spelling of 28321216 in words is "twenty-eight million, three hundred twenty-one thousand, two hundred sixteen".