28021204 has 24 divisors (see below), whose sum is σ = 51074856. Its totient is φ = 13440000.

The previous prime is 28021193. The next prime is 28021207. The reversal of 28021204 is 40212082.

It can be written as a sum of positive squares in 4 ways, for example, as 960400 + 27060804 = 980^2 + 5202^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28021207) 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 7 ways as a sum of consecutive naturals, for example, 8604 + ... + 11404.

It is an arithmetic number, because the mean of its divisors is an integer number (2128119).

Almost surely, 2^28021204 is an apocalyptic number.

It is an amenable number.

28021204 is a deficient number, since it is larger than the sum of its proper divisors (23053652).

28021204 is a wasteful number, since it uses less digits than its factorization.

28021204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2907 (or 2905 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 28021204 is about 5293.5058326217. The cubic root of 28021204 is about 303.7355300281.

Adding to 28021204 its reverse (40212082), we get a palindrome (68233286).

The spelling of 28021204 in words is "twenty-eight million, twenty-one thousand, two hundred four".