28168821 has 12 divisors (see below), whose sum is σ = 40748448. Its totient is φ = 18751464.

The previous prime is 28168807. The next prime is 28168823. The reversal of 28168821 is 12886182.

It is not a de Polignac number, because 28168821 - 2⁶ = 28168757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28168823) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5506 + ... + 9308.

It is an arithmetic number, because the mean of its divisors is an integer number (3395704).

Almost surely, 2^28168821 is an apocalyptic number.

It is an amenable number.

28168821 is a deficient number, since it is larger than the sum of its proper divisors (12579627).

28168821 is a wasteful number, since it uses less digits than its factorization.

28168821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4632 (or 4629 counting only the distinct ones).

The product of its digits is 12288, while the sum is 36.

The square root of 28168821 is about 5307.4307343573. The cubic root of 28168821 is about 304.2679604419.

The spelling of 28168821 in words is "twenty-eight million, one hundred sixty-eight thousand, eight hundred twenty-one".