22181909 has 2 divisors, whose sum is σ = 22181910. Its totient is φ = 22181908.

The previous prime is 22181893. The next prime is 22181917. The reversal of 22181909 is 90918122.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21362884 + 819025 = 4622^2 + 905^2 .

It is a cyclic number.

It is not a de Polignac number, because 22181909 - 2⁴ = 22181893 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22181989) 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, 11090954 + 11090955.

It is an arithmetic number, because the mean of its divisors is an integer number (11090955).

Almost surely, 2^22181909 is an apocalyptic number.

It is an amenable number.

22181909 is a deficient number, since it is larger than the sum of its proper divisors (1).

22181909 is an equidigital number, since it uses as much as digits as its factorization.

22181909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 22181909 is about 4709.7674040233. The cubic root of 22181909 is about 280.9741114180.

The spelling of 22181909 in words is "twenty-two million, one hundred eighty-one thousand, nine hundred nine".