28003866 has 32 divisors (see below), whose sum is σ = 61718976. Its totient is φ = 8400000.

The previous prime is 28003831. The next prime is 28003873. The reversal of 28003866 is 66830082.

It is a Harshad number since it is a multiple of its sum of digits (33).

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 15 ways as a sum of consecutive naturals, for example, 4566 + ... + 8766.

It is an arithmetic number, because the mean of its divisors is an integer number (1928718).

Almost surely, 2^28003866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28003866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30859488).

28003866 is an abundant number, since it is smaller than the sum of its proper divisors (33715110).

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

28003866 is a wasteful number, since it uses less digits than its factorization.

28003866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4318.

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 28003866 is about 5291.8679121837. The cubic root of 28003866 is about 303.6728720837.

It can be divided in two parts, 2800 and 3866, that added together give a palindrome (6666).

The spelling of 28003866 in words is "twenty-eight million, three thousand, eight hundred sixty-six".