28163309 has 2 divisors, whose sum is σ = 28163310. Its totient is φ = 28163308.

The previous prime is 28163287. The next prime is 28163341. The reversal of 28163309 is 90336182.

It is an a-pointer prime, because the next prime (28163341) can be obtained adding 28163309 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20340100 + 7823209 = 4510^2 + 2797^2 .

It is a cyclic number.

It is not a de Polignac number, because 28163309 - 2⁸ = 28163053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28160309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14081654 + 14081655.

It is an arithmetic number, because the mean of its divisors is an integer number (14081655).

Almost surely, 2^28163309 is an apocalyptic number.

It is an amenable number.

28163309 is a deficient number, since it is larger than the sum of its proper divisors (1).

28163309 is an equidigital number, since it uses as much as digits as its factorization.

28163309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 28163309 is about 5306.9114369848. The cubic root of 28163309 is about 304.2481130321.

The spelling of 28163309 in words is "twenty-eight million, one hundred sixty-three thousand, three hundred nine".