28023821 has 8 divisors (see below), whose sum is σ = 33419904. Its totient is φ = 22975920.

The previous prime is 28023811. The next prime is 28023823. The reversal of 28023821 is 12832082.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28023821 - 2⁶ = 28023757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28023823) 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, 86870 + ... + 87191.

It is an arithmetic number, because the mean of its divisors is an integer number (4177488).

Almost surely, 2^28023821 is an apocalyptic number.

It is an amenable number.

28023821 is a deficient number, since it is larger than the sum of its proper divisors (5396083).

28023821 is a wasteful number, since it uses less digits than its factorization.

28023821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174091.

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 28023821 is about 5293.7530165281. The cubic root of 28023821 is about 303.7449853813.

The spelling of 28023821 in words is "twenty-eight million, twenty-three thousand, eight hundred twenty-one".