28105939 has 4 divisors (see below), whose sum is σ = 28308280. Its totient is φ = 27903600.

The previous prime is 28105937. The next prime is 28105943. The reversal of 28105939 is 93950182.

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 28105939 - 2¹ = 28105937 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28105898 and 28105907.

It is not an unprimeable number, because it can be changed into a prime (28105937) 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, 100962 + ... + 101239.

It is an arithmetic number, because the mean of its divisors is an integer number (7077070).

Almost surely, 2^28105939 is an apocalyptic number.

28105939 is a deficient number, since it is larger than the sum of its proper divisors (202341).

28105939 is a wasteful number, since it uses less digits than its factorization.

28105939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202340.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 28105939 is about 5301.5034659991. The cubic root of 28105939 is about 304.0413833032.

The spelling of 28105939 in words is "twenty-eight million, one hundred five thousand, nine hundred thirty-nine".