28821004 has 12 divisors (see below), whose sum is σ = 50491728. Its totient is φ = 14394800.

The previous prime is 28820993. The next prime is 28821049. The reversal of 28821004 is 40012882.

It is a self number, because there is not a number n which added to its sum of digits gives 28821004.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 849 + ... + 7639.

It is an arithmetic number, because the mean of its divisors is an integer number (4207644).

Almost surely, 2^28821004 is an apocalyptic number.

It is an amenable number.

28821004 is a deficient number, since it is larger than the sum of its proper divisors (21670724).

28821004 is a wasteful number, since it uses less digits than its factorization.

28821004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7856 (or 7854 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 28821004 is about 5368.5197214875. The cubic root of 28821004 is about 306.5982713465.

Adding to 28821004 its reverse (40012882), we get a palindrome (68833886).

The spelling of 28821004 in words is "twenty-eight million, eight hundred twenty-one thousand, four".