28021986 has 24 divisors (see below), whose sum is σ = 61027200. Its totient is φ = 9292536.

The previous prime is 28021969. The next prime is 28021993. The reversal of 28021986 is 68912082.

It is a self number, because there is not a number n which added to its sum of digits gives 28021986.

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 11 ways as a sum of consecutive naturals, for example, 330 + ... + 7493.

It is an arithmetic number, because the mean of its divisors is an integer number (2542800).

Almost surely, 2^28021986 is an apocalyptic number.

28021986 is an abundant number, since it is smaller than the sum of its proper divisors (33005214).

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

28021986 is a wasteful number, since it uses less digits than its factorization.

28021986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8030 (or 8027 counting only the distinct ones).

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

The square root of 28021986 is about 5293.5796961980. The cubic root of 28021986 is about 303.7383554953.

The spelling of 28021986 in words is "twenty-eight million, twenty-one thousand, nine hundred eighty-six".