28808021 has 8 divisors (see below), whose sum is σ = 32441088. Its totient is φ = 25344000.

The previous prime is 28808011. The next prime is 28808051. The reversal of 28808021 is 12080882.

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

It is not a de Polignac number, because 28808021 - 2²² = 24613717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28808011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41900 + ... + 42581.

It is an arithmetic number, because the mean of its divisors is an integer number (4055136).

Almost surely, 2^28808021 is an apocalyptic number.

It is an amenable number.

28808021 is a deficient number, since it is larger than the sum of its proper divisors (3633067).

28808021 is a wasteful number, since it uses less digits than its factorization.

28808021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84523.

The product of its (nonzero) digits is 2048, while the sum is 29.

The square root of 28808021 is about 5367.3104065258. The cubic root of 28808021 is about 306.5522266492.

It can be divided in two parts, 2880 and 8021, that added together give a palindrome (10901).

The spelling of 28808021 in words is "twenty-eight million, eight hundred eight thousand, twenty-one".