28115909 has 8 divisors (see below), whose sum is σ = 29830680. Its totient is φ = 26407936.

The previous prime is 28115897. The next prime is 28115939. The reversal of 28115909 is 90951182.

It can be written as a sum of positive squares in 4 ways, for example, as 10660225 + 17455684 = 3265^2 + 4178^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28115909 - 2²⁴ = 11338693 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 (28115939) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8687 + ... + 11475.

It is an arithmetic number, because the mean of its divisors is an integer number (3728835).

Almost surely, 2^28115909 is an apocalyptic number.

It is an amenable number.

28115909 is a deficient number, since it is larger than the sum of its proper divisors (1714771).

28115909 is a wasteful number, since it uses less digits than its factorization.

28115909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3399.

The product of its (nonzero) digits is 6480, while the sum is 35.

The square root of 28115909 is about 5302.4436819263. The cubic root of 28115909 is about 304.0773298486.

The spelling of 28115909 in words is "twenty-eight million, one hundred fifteen thousand, nine hundred nine".