28108231 has 4 divisors (see below), whose sum is σ = 29330352. Its totient is φ = 26886112.

The previous prime is 28108229. The next prime is 28108243. The reversal of 28108231 is 13280182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13280182 = 2 ⋅6640091.

It is a cyclic number.

It is not a de Polignac number, because 28108231 - 2¹ = 28108229 is a prime.

It is a super-2 number, since 2×28108231² = 1580145299898722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28108196 and 28108205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28108211) 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, 611026 + ... + 611071.

It is an arithmetic number, because the mean of its divisors is an integer number (7332588).

Almost surely, 2^28108231 is an apocalyptic number.

28108231 is a deficient number, since it is larger than the sum of its proper divisors (1222121).

28108231 is a wasteful number, since it uses less digits than its factorization.

28108231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222120.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 28108231 is about 5301.7196266872. The cubic root of 28108231 is about 304.0496477951.

The spelling of 28108231 in words is "twenty-eight million, one hundred eight thousand, two hundred thirty-one".