28221868 has 12 divisors (see below), whose sum is σ = 49568512. Its totient is φ = 14059440.

The previous prime is 28221847. The next prime is 28221871. The reversal of 28221868 is 86812282.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

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, 11628 + ... + 13843.

Almost surely, 2^28221868 is an apocalyptic number.

It is an amenable number.

28221868 is a deficient number, since it is larger than the sum of its proper divisors (21346644).

28221868 is a wasteful number, since it uses less digits than its factorization.

28221868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25752 (or 25750 counting only the distinct ones).

The product of its digits is 24576, while the sum is 37.

The square root of 28221868 is about 5312.4258112467. The cubic root of 28221868 is about 304.4588379285.

The spelling of 28221868 in words is "twenty-eight million, two hundred twenty-one thousand, eight hundred sixty-eight".