28366821 has 16 divisors (see below), whose sum is σ = 48028800. Its totient is φ = 16209504.

The previous prime is 28366817. The next prime is 28366823. The reversal of 28366821 is 12866382.

It is not a de Polignac number, because 28366821 - 2² = 28366817 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 (28366823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74856 + ... + 75233.

It is an arithmetic number, because the mean of its divisors is an integer number (3001800).

Almost surely, 2^28366821 is an apocalyptic number.

28366821 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28366821 is a deficient number, since it is larger than the sum of its proper divisors (19661979).

28366821 is a wasteful number, since it uses less digits than its factorization.

28366821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150105 (or 150099 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 28366821 is about 5326.0511638549. The cubic root of 28366821 is about 304.9792013050.

The spelling of 28366821 in words is "twenty-eight million, three hundred sixty-six thousand, eight hundred twenty-one".