28021896 has 128 divisors (see below), whose sum is σ = 91238400. Its totient is φ = 7801920.

The previous prime is 28021883. The next prime is 28021897. The reversal of 28021896 is 69812082.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 28021896.

It is not an unprimeable number, because it can be changed into a prime (28021897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 64801 + ... + 65231.

It is an arithmetic number, because the mean of its divisors is an integer number (712800).

Almost surely, 2^28021896 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28021896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45619200).

28021896 is an abundant number, since it is smaller than the sum of its proper divisors (63216504).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28021896 is a wasteful number, since it uses less digits than its factorization.

28021896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 496 (or 486 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 28021896 is about 5293.5711953274. The cubic root of 28021896 is about 303.7380303163.

The spelling of 28021896 in words is "twenty-eight million, twenty-one thousand, eight hundred ninety-six".