28126809 has 12 divisors (see below), whose sum is σ = 40792752. Its totient is φ = 18675000.

The previous prime is 28126793. The next prime is 28126843. The reversal of 28126809 is 90862182.

It is not a de Polignac number, because 28126809 - 2⁴ = 28126793 is a prime.

It is a super-2 number, since 2×28126809² = 1582234769044962, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28126849) 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, 3967 + ... + 8484.

It is an arithmetic number, because the mean of its divisors is an integer number (3399396).

Almost surely, 2^28126809 is an apocalyptic number.

It is an amenable number.

28126809 is a deficient number, since it is larger than the sum of its proper divisors (12665943).

28126809 is a wasteful number, since it uses less digits than its factorization.

28126809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12708 (or 12705 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 28126809 is about 5303.4714103123. The cubic root of 28126809 is about 304.1166197594.

The spelling of 28126809 in words is "twenty-eight million, one hundred twenty-six thousand, eight hundred nine".