28142821 has 8 divisors (see below), whose sum is σ = 32235840. Its totient is φ = 24067968.

The previous prime is 28142809. The next prime is 28142827. The reversal of 28142821 is 12824182.

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 28142821 - 2⁷ = 28142693 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28142821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28142827) 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, 1036 + ... + 7573.

It is an arithmetic number, because the mean of its divisors is an integer number (4029480).

Almost surely, 2^28142821 is an apocalyptic number.

It is an amenable number.

28142821 is a deficient number, since it is larger than the sum of its proper divisors (4093019).

28142821 is an equidigital number, since it uses as much as digits as its factorization.

28142821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9083.

The product of its digits is 2048, while the sum is 28.

The square root of 28142821 is about 5304.9807728210. The cubic root of 28142821 is about 304.1743178743.

The spelling of 28142821 in words is "twenty-eight million, one hundred forty-two thousand, eight hundred twenty-one".