28290109 has 4 divisors (see below), whose sum is σ = 29265660. Its totient is φ = 27314560.

The previous prime is 28290103. The next prime is 28290127. The reversal of 28290109 is 90109282.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19272100 + 9018009 = 4390^2 + 3003^2 .

It is a cyclic number.

It is not a de Polignac number, because 28290109 - 2⁷ = 28289981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28290103) 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, 487732 + ... + 487789.

It is an arithmetic number, because the mean of its divisors is an integer number (7316415).

Almost surely, 2^28290109 is an apocalyptic number.

28290109 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

28290109 is a deficient number, since it is larger than the sum of its proper divisors (975551).

28290109 is an equidigital number, since it uses as much as digits as its factorization.

28290109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 975550.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 28290109 is about 5318.8447053848. The cubic root of 28290109 is about 304.7040361080.

The spelling of 28290109 in words is "twenty-eight million, two hundred ninety thousand, one hundred nine".