28117111 has 4 divisors (see below), whose sum is σ = 30673224. Its totient is φ = 25561000.

The previous prime is 28117097. The next prime is 28117121. The reversal of 28117111 is 11171182.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28117111 - 2⁵ = 28117079 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28117121) 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 3 ways as a sum of consecutive naturals, for example, 1278040 + ... + 1278061.

It is an arithmetic number, because the mean of its divisors is an integer number (7668306).

Almost surely, 2^28117111 is an apocalyptic number.

28117111 is a deficient number, since it is larger than the sum of its proper divisors (2556113).

28117111 is a wasteful number, since it uses less digits than its factorization.

28117111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2556112.

The product of its digits is 112, while the sum is 22.

The square root of 28117111 is about 5302.5570246816. The cubic root of 28117111 is about 304.0816630506.

Adding to 28117111 its reverse (11171182), we get a palindrome (39288293).

It can be divided in two parts, 281171 and 11, that added together give a palindrome (281182).

The spelling of 28117111 in words is "twenty-eight million, one hundred seventeen thousand, one hundred eleven".