28785281 has 16 divisors (see below), whose sum is σ = 33547008. Its totient is φ = 24192000.

The previous prime is 28785271. The next prime is 28785283. The reversal of 28785281 is 18258782.

It is not a de Polignac number, because 28785281 - 2¹⁴ = 28768897 is a prime.

It is a super-2 number, since 2×28785281² = 1657184804497922, which contains 22 as substring.

It is a Duffinian number.

Its product of digits (71680) is a multiple of the sum of its prime divisors (512).

It is not an unprimeable number, because it can be changed into a prime (28785283) by changing a digit.

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, 119321 + ... + 119561.

It is an arithmetic number, because the mean of its divisors is an integer number (2096688).

Almost surely, 2^28785281 is an apocalyptic number.

It is an amenable number.

28785281 is a deficient number, since it is larger than the sum of its proper divisors (4761727).

28785281 is a wasteful number, since it uses less digits than its factorization.

28785281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512.

The product of its digits is 71680, while the sum is 41.

The square root of 28785281 is about 5365.1916088803. The cubic root of 28785281 is about 306.4715450379.

The spelling of 28785281 in words is "twenty-eight million, seven hundred eighty-five thousand, two hundred eighty-one".