28108281 has 4 divisors (see below), whose sum is σ = 37477712. Its totient is φ = 18738852.

The previous prime is 28108243. The next prime is 28108307. The reversal of 28108281 is 18280182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28108281 - 2⁶ = 28108217 is a prime.

It is a super-2 number, since 2×28108281² = 1580150921549922, which contains 22 as substring.

It is a Duffinian 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, 4684711 + ... + 4684716.

It is an arithmetic number, because the mean of its divisors is an integer number (9369428).

Almost surely, 2^28108281 is an apocalyptic number.

It is an amenable number.

28108281 is a deficient number, since it is larger than the sum of its proper divisors (9369431).

28108281 is an equidigital number, since it uses as much as digits as its factorization.

28108281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9369430.

The product of its (nonzero) digits is 2048, while the sum is 30.

The square root of 28108281 is about 5301.7243421362. The cubic root of 28108281 is about 304.0498280800.

The spelling of 28108281 in words is "twenty-eight million, one hundred eight thousand, two hundred eighty-one".