28163791 has 4 divisors (see below), whose sum is σ = 28427112. Its totient is φ = 27900472.

The previous prime is 28163789. The next prime is 28163801. The reversal of 28163791 is 19736182.

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 28163791 - 2¹ = 28163789 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28163791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28163731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131500 + ... + 131713.

It is an arithmetic number, because the mean of its divisors is an integer number (7106778).

Almost surely, 2^28163791 is an apocalyptic number.

28163791 is a deficient number, since it is larger than the sum of its proper divisors (263321).

28163791 is a wasteful number, since it uses less digits than its factorization.

28163791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263320.

The product of its digits is 18144, while the sum is 37.

The square root of 28163791 is about 5306.9568492687. The cubic root of 28163791 is about 304.2498487036.

The spelling of 28163791 in words is "twenty-eight million, one hundred sixty-three thousand, seven hundred ninety-one".