28813909 has 2 divisors, whose sum is σ = 28813910. Its totient is φ = 28813908.

The previous prime is 28813901. The next prime is 28813919. The reversal of 28813909 is 90931882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26811684 + 2002225 = 5178^2 + 1415^2 .

It is a cyclic number.

It is not a de Polignac number, because 28813909 - 2³ = 28813901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28813901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14406954 + 14406955.

It is an arithmetic number, because the mean of its divisors is an integer number (14406955).

Almost surely, 2^28813909 is an apocalyptic number.

It is an amenable number.

28813909 is a deficient number, since it is larger than the sum of its proper divisors (1).

28813909 is an equidigital number, since it uses as much as digits as its factorization.

28813909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 28813909 is about 5367.8588841362. The cubic root of 28813909 is about 306.5731103764.

The spelling of 28813909 in words is "twenty-eight million, eight hundred thirteen thousand, nine hundred nine".