22128809 has 2 divisors, whose sum is σ = 22128810. Its totient is φ = 22128808.

The previous prime is 22128803. The next prime is 22128811. The reversal of 22128809 is 90882122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22090000 + 38809 = 4700^2 + 197^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-22128809 is a prime.

Together with 22128811, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (22128803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11064404 + 11064405.

It is an arithmetic number, because the mean of its divisors is an integer number (11064405).

Almost surely, 2^22128809 is an apocalyptic number.

It is an amenable number.

22128809 is a deficient number, since it is larger than the sum of its proper divisors (1).

22128809 is an equidigital number, since it uses as much as digits as its factorization.

22128809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 22128809 is about 4704.1268052637. The cubic root of 22128809 is about 280.7497296732.

The spelling of 22128809 in words is "twenty-two million, one hundred twenty-eight thousand, eight hundred nine".