28821665 has 8 divisors (see below), whose sum is σ = 35238888. Its totient is φ = 22622080.

The previous prime is 28821643. The next prime is 28821673. The reversal of 28821665 is 56612882.

It can be written as a sum of positive squares in 4 ways, for example, as 10784656 + 18037009 = 3284^2 + 4247^2 .

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

It is not a de Polignac number, because 28821665 - 2⁶ = 28821601 is a prime.

It is a Duffinian number.

It is a Curzon number.

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 7 ways as a sum of consecutive naturals, for example, 54116 + ... + 54645.

It is an arithmetic number, because the mean of its divisors is an integer number (4404861).

Almost surely, 2^28821665 is an apocalyptic number.

It is an amenable number.

28821665 is a deficient number, since it is larger than the sum of its proper divisors (6417223).

28821665 is a wasteful number, since it uses less digits than its factorization.

28821665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108819.

The product of its digits is 46080, while the sum is 38.

The square root of 28821665 is about 5368.5812837285. The cubic root of 28821665 is about 306.6006152379.

The spelling of 28821665 in words is "twenty-eight million, eight hundred twenty-one thousand, six hundred sixty-five".