28303681 has 16 divisors (see below), whose sum is σ = 33978240. Its totient is φ = 23063040.

The previous prime is 28303669. The next prime is 28303687. The reversal of 28303681 is 18630382.

It is not a de Polignac number, because 28303681 - 2⁷ = 28303553 is a prime.

It is a super-2 number, since 2×28303681² = 1602196716299522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28303687) 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, 12561 + ... + 14641.

It is an arithmetic number, because the mean of its divisors is an integer number (2123640).

Almost surely, 2^28303681 is an apocalyptic number.

It is an amenable number.

28303681 is a deficient number, since it is larger than the sum of its proper divisors (5674559).

28303681 is a wasteful number, since it uses less digits than its factorization.

28303681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2184.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 28303681 is about 5320.1203933746. The cubic root of 28303681 is about 304.7527549263.

The spelling of 28303681 in words is "twenty-eight million, three hundred three thousand, six hundred eighty-one".