28385909 has 2 divisors, whose sum is σ = 28385910. Its totient is φ = 28385908.

The previous prime is 28385881. The next prime is 28385911. The reversal of 28385909 is 90958382.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27615025 + 770884 = 5255^2 + 878^2 .

It is a cyclic number.

It is not a de Polignac number, because 28385909 - 2¹⁶ = 28320373 is a prime.

Together with 28385911, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28385909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28385969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14192954 + 14192955.

It is an arithmetic number, because the mean of its divisors is an integer number (14192955).

Almost surely, 2^28385909 is an apocalyptic number.

It is an amenable number.

28385909 is a deficient number, since it is larger than the sum of its proper divisors (1).

28385909 is an equidigital number, since it uses as much as digits as its factorization.

28385909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 28385909 is about 5327.8428092428. The cubic root of 28385909 is about 305.0475926807.

The spelling of 28385909 in words is "twenty-eight million, three hundred eighty-five thousand, nine hundred nine".