28109939 has 12 divisors (see below), whose sum is σ = 33207912. Its totient is φ = 23587200.

The previous prime is 28109929. The next prime is 28109947. The reversal of 28109939 is 93990182.

It is not a de Polignac number, because 28109939 - 2¹⁶ = 28044403 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28109896 and 28109905.

It is not an unprimeable number, because it can be changed into a prime (28109929) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5702 + ... + 9419.

It is an arithmetic number, because the mean of its divisors is an integer number (2767326).

Almost surely, 2^28109939 is an apocalyptic number.

28109939 is a deficient number, since it is larger than the sum of its proper divisors (5097973).

28109939 is a wasteful number, since it uses less digits than its factorization.

28109939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15158 (or 15145 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 28109939 is about 5301.8807040521. The cubic root of 28109939 is about 304.0558062080.

The spelling of 28109939 in words is "twenty-eight million, one hundred nine thousand, nine hundred thirty-nine".